diff --git a/CHANGELOG.md b/CHANGELOG.md
index acc28539..87e4de10 100755
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,12 @@
 - Fixed wrong mapping of `NavigationAction` class on Android for `androidHasGesture` and `androidIsRedirect` properties
 - Fixed "Pull to refresh creating problem in some webpages on Android" [#719](https://github.com/pichillilorenzo/flutter_inappwebview/issues/719)
 - Fixed iOS sometimes `scrollView.contentSize` doesn't fit all the `frame.size` available
+- Fixed ajax and fetch interceptor when the data/body sent is not a string
+- Fixed "InAppLocalhostServer - Error: type 'List<dynamic>' is not a subtype of type 'List<int>' in type cast" [#724](https://github.com/pichillilorenzo/flutter_inappwebview/issues/724)
+
+### BREAKING CHANGES
+
+- `FetchRequest.body` is a dynamic type now
 
 ## 5.1.0+4
 
diff --git a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/Util.java b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/Util.java
index 4a0b45b1..d88d3d6b 100755
--- a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/Util.java
+++ b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/Util.java
@@ -274,4 +274,17 @@ public class Util {
   public static String replaceAll(String s, String oldString, String newString) {
     return TextUtils.join(newString, s.split(Pattern.quote(oldString)));
   }
+
+  public static void log(String tag, String message) {
+    // Split by line, then ensure each line can fit into Log's maximum length.
+    for (int i = 0, length = message.length(); i < length; i++) {
+      int newline = message.indexOf('\n', i);
+      newline = newline != -1 ? newline : length;
+      do {
+        int end = Math.min(newline, i + 4000);
+        Log.d(tag, message.substring(i, end));
+        i = end;
+      } while (i < newline);
+    }
+  }
 }
diff --git a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/plugin_scripts_js/InterceptAjaxRequestJS.java b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/plugin_scripts_js/InterceptAjaxRequestJS.java
index dba3246e..9dbcba6d 100644
--- a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/plugin_scripts_js/InterceptAjaxRequestJS.java
+++ b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/plugin_scripts_js/InterceptAjaxRequestJS.java
@@ -183,46 +183,63 @@ public class InterceptAjaxRequestJS {
           "      this.addEventListener('error', handleEvent);" +
           "      this.addEventListener('abort', handleEvent);" +
           "      this.addEventListener('timeout', handleEvent);" +
-          "      var ajaxRequest = {" +
-          "        data: data," +
-          "        method: this._flutter_inappwebview_method," +
-          "        url: this._flutter_inappwebview_url," +
-          "        isAsync: this._flutter_inappwebview_isAsync," +
-          "        user: this._flutter_inappwebview_user," +
-          "        password: this._flutter_inappwebview_password," +
-          "        withCredentials: this.withCredentials," +
-          "        headers: this._flutter_inappwebview_request_headers," +
-          "        responseType: this.responseType" +
-          "      };" +
-          "      window." + JavaScriptBridgeJS.JAVASCRIPT_BRIDGE_NAME + ".callHandler('shouldInterceptAjaxRequest', ajaxRequest).then(function(result) {" +
-          "        if (result != null) {" +
-          "          switch (result.action) {" +
-          "            case 0:" +
-          "              self.abort();" +
-          "              return;" +
-          "          };" +
-          "          data = result.data;" +
-          "          self.withCredentials = result.withCredentials;" +
-          "          if (result.responseType != null) {" +
-          "            self.responseType = result.responseType;" +
-          "          };" +
-          "          for (var header in result.headers) {" +
-          "            var value = result.headers[header];" +
-          "            var flutter_inappwebview_value = self._flutter_inappwebview_request_headers[header];" +
-          "            if (flutter_inappwebview_value == null) {" +
-          "              self._flutter_inappwebview_request_headers[header] = value;" +
-          "            } else {" +
-          "              self._flutter_inappwebview_request_headers[header] += ', ' + value;" +
+          "      " + JavaScriptBridgeJS.JAVASCRIPT_UTIL_VAR_NAME + ".convertBodyRequest(data).then(function(data) {" +
+          "        var ajaxRequest = {" +
+          "          data: data," +
+          "          method: self._flutter_inappwebview_method," +
+          "          url: self._flutter_inappwebview_url," +
+          "          isAsync: self._flutter_inappwebview_isAsync," +
+          "          user: self._flutter_inappwebview_user," +
+          "          password: self._flutter_inappwebview_password," +
+          "          withCredentials: self.withCredentials," +
+          "          headers: self._flutter_inappwebview_request_headers," +
+          "          responseType: self.responseType" +
+          "        };" +
+          "        window." + JavaScriptBridgeJS.JAVASCRIPT_BRIDGE_NAME + ".callHandler('shouldInterceptAjaxRequest', ajaxRequest).then(function(result) {" +
+          "          if (result != null) {" +
+          "            switch (result.action) {" +
+          "              case 0:" +
+          "                self.abort();" +
+          "                return;" +
+          "            };" +
+          "            if (result.data != null && !" + JavaScriptBridgeJS.JAVASCRIPT_UTIL_VAR_NAME + ".isString(result.data) && result.data.length > 0) {" +
+          "              var bodyString = " + JavaScriptBridgeJS.JAVASCRIPT_UTIL_VAR_NAME + ".arrayBufferToString(result.data);" +
+          "              if (" + JavaScriptBridgeJS.JAVASCRIPT_UTIL_VAR_NAME + ".isBodyFormData(bodyString)) {" +
+          "                var formDataContentType = " + JavaScriptBridgeJS.JAVASCRIPT_UTIL_VAR_NAME + ".getFormDataContentType(bodyString);" +
+          "                if (result.headers != null) {" +
+          "                  result.headers['Content-Type'] = result.headers['Content-Type'] == null ? formDataContentType : result.headers['Content-Type'];" +
+          "                } else {" +
+          "                  result.headers = { 'Content-Type': formDataContentType };" +
+          "                }" +
+          "              }" +
+          "            }" +
+          "            if (" + JavaScriptBridgeJS.JAVASCRIPT_UTIL_VAR_NAME + ".isString(result.data) || result.data == null) {" +
+          "              data = result.data;" +
+          "            } else if (result.data.length > 0) {" +
+          "              data = new Uint8Array(result.data);" +
+          "            }" +
+          "            self.withCredentials = result.withCredentials;" +
+          "            if (result.responseType != null) {" +
+          "              self.responseType = result.responseType;" +
+          "            };" +
+          "            for (var header in result.headers) {" +
+          "              var value = result.headers[header];" +
+          "              var flutter_inappwebview_value = self._flutter_inappwebview_request_headers[header];" +
+          "              if (flutter_inappwebview_value == null) {" +
+          "                self._flutter_inappwebview_request_headers[header] = value;" +
+          "              } else {" +
+          "                self._flutter_inappwebview_request_headers[header] += ', ' + value;" +
+          "              }" +
+          "              setRequestHeader.call(self, header, value);" +
+          "            };" +
+          "            if ((self._flutter_inappwebview_method != result.method && result.method != null) || (self._flutter_inappwebview_url != result.url && result.url != null)) {" +
+          "              self.abort();" +
+          "              self.open(result.method, result.url, result.isAsync, result.user, result.password);" +
+          "              return;" +
           "            }" +
-          "            setRequestHeader.call(self, header, value);" +
-          "          };" +
-          "          if ((self._flutter_inappwebview_method != result.method && result.method != null) || (self._flutter_inappwebview_url != result.url && result.url != null)) {" +
-          "            self.abort();" +
-          "            self.open(result.method, result.url, result.isAsync, result.user, result.password);" +
-          "            return;" +
           "          }" +
-          "        }" +
-          "        send.call(self, data);" +
+          "          send.call(self, data);" +
+          "        });" +
           "      });" +
           "    } else {" +
           "      send.call(this, data);" +
diff --git a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/plugin_scripts_js/InterceptFetchRequestJS.java b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/plugin_scripts_js/InterceptFetchRequestJS.java
index bac04c0d..f5d833eb 100644
--- a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/plugin_scripts_js/InterceptFetchRequestJS.java
+++ b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/plugin_scripts_js/InterceptFetchRequestJS.java
@@ -21,68 +21,6 @@ public class InterceptFetchRequestJS {
           "  if (fetch == null) {" +
           "    return;" +
           "  }" +
-          "  function convertHeadersToJson(headers) {" +
-          "    var headersObj = {};" +
-          "    for (var header of headers.keys()) {" +
-          "      var value = headers.get(header);" +
-          "      headersObj[header] = value;" +
-          "    }" +
-          "    return headersObj;" +
-          "  }" +
-          "  function convertJsonToHeaders(headersJson) {" +
-          "    return new Headers(headersJson);" +
-          "  }" +
-          "  function convertBodyToArray(body) {" +
-          "    return new Response(body).arrayBuffer().then(function(arrayBuffer) {" +
-          "      var arr = Array.from(new Uint8Array(arrayBuffer));" +
-          "      return arr;" +
-          "    })" +
-          "  }" +
-          "  function convertArrayIntBodyToUint8Array(arrayIntBody) {" +
-          "    return new Uint8Array(arrayIntBody);" +
-          "  }" +
-          "  function convertCredentialsToJson(credentials) {" +
-          "    var credentialsObj = {};" +
-          "    if (window.FederatedCredential != null && credentials instanceof FederatedCredential) {" +
-          "      credentialsObj.type = credentials.type;" +
-          "      credentialsObj.id = credentials.id;" +
-          "      credentialsObj.name = credentials.name;" +
-          "      credentialsObj.protocol = credentials.protocol;" +
-          "      credentialsObj.provider = credentials.provider;" +
-          "      credentialsObj.iconURL = credentials.iconURL;" +
-          "    } else if (window.PasswordCredential != null && credentials instanceof PasswordCredential) {" +
-          "      credentialsObj.type = credentials.type;" +
-          "      credentialsObj.id = credentials.id;" +
-          "      credentialsObj.name = credentials.name;" +
-          "      credentialsObj.password = credentials.password;" +
-          "      credentialsObj.iconURL = credentials.iconURL;" +
-          "    } else {" +
-          "      credentialsObj.type = 'default';" +
-          "      credentialsObj.value = credentials;" +
-          "    }" +
-          "  }" +
-          "  function convertJsonToCredential(credentialsJson) {" +
-          "    var credentials;" +
-          "    if (window.FederatedCredential != null && credentialsJson.type === 'federated') {" +
-          "      credentials = new FederatedCredential({" +
-          "        id: credentialsJson.id," +
-          "        name: credentialsJson.name," +
-          "        protocol: credentialsJson.protocol," +
-          "        provider: credentialsJson.provider," +
-          "        iconURL: credentialsJson.iconURL" +
-          "      });" +
-          "    } else if (window.PasswordCredential != null && credentialsJson.type === 'password') {" +
-          "      credentials = new PasswordCredential({" +
-          "        id: credentialsJson.id," +
-          "        name: credentialsJson.name," +
-          "        password: credentialsJson.password," +
-          "        iconURL: credentialsJson.iconURL" +
-          "      });" +
-          "    } else {" +
-          "      credentials = credentialsJson;" +
-          "    }" +
-          "    return credentials;" +
-          "  }" +
           "  window.fetch = async function(resource, init) {" +
           "    var w = (window.top == null || window.top === window) ? window : window.top;" +
           "    if (w." + FLAG_VARIABLE_FOR_SHOULD_INTERCEPT_FETCH_REQUEST_JS_SOURCE + " == null || w." + FLAG_VARIABLE_FOR_SHOULD_INTERCEPT_FETCH_REQUEST_JS_SOURCE + " == true) {" +
@@ -114,7 +52,7 @@ public class InterceptFetchRequestJS {
           "        fetchRequest.integrity = resource.integrity;" +
           "        fetchRequest.keepalive = resource.keepalive;" +
           "      } else {" +
-          "        fetchRequest.url = resource;" +
+          "        fetchRequest.url = resource != null ? resource.toString() : null;" +
           "        if (init != null) {" +
           "          fetchRequest.method = init.method;" +
           "          fetchRequest.headers = init.headers;" +
@@ -130,10 +68,10 @@ public class InterceptFetchRequestJS {
           "        }" +
           "      }" +
           "      if (fetchRequest.headers instanceof Headers) {" +
-          "        fetchRequest.headers = convertHeadersToJson(fetchRequest.headers);" +
+          "        fetchRequest.headers = " + JavaScriptBridgeJS.JAVASCRIPT_UTIL_VAR_NAME + ".convertHeadersToJson(fetchRequest.headers);" +
           "      }" +
-          "      fetchRequest.credentials = convertCredentialsToJson(fetchRequest.credentials);" +
-          "      return convertBodyToArray(fetchRequest.body).then(function(body) {" +
+          "      fetchRequest.credentials = " + JavaScriptBridgeJS.JAVASCRIPT_UTIL_VAR_NAME + ".convertCredentialsToJson(fetchRequest.credentials);" +
+          "      return " + JavaScriptBridgeJS.JAVASCRIPT_UTIL_VAR_NAME + ".convertBodyRequest(fetchRequest.body).then(function(body) {" +
           "        fetchRequest.body = body;" +
           "        return window." + JavaScriptBridgeJS.JAVASCRIPT_BRIDGE_NAME + ".callHandler('shouldInterceptFetchRequest', fetchRequest).then(function(result) {" +
           "          if (result != null) {" +
@@ -150,7 +88,18 @@ public class InterceptFetchRequestJS {
           "                controller.abort();" +
           "                break;" +
           "            }" +
-          "            resource = (result.url != null) ? result.url : resource;" +
+          "            if (result.body != null && !" + JavaScriptBridgeJS.JAVASCRIPT_UTIL_VAR_NAME + ".isString(result.body) && result.body.length > 0) {" +
+          "              var bodyString = " + JavaScriptBridgeJS.JAVASCRIPT_UTIL_VAR_NAME + ".arrayBufferToString(result.body);" +
+          "              if (" + JavaScriptBridgeJS.JAVASCRIPT_UTIL_VAR_NAME + ".isBodyFormData(bodyString)) {" +
+          "                var formDataContentType = " + JavaScriptBridgeJS.JAVASCRIPT_UTIL_VAR_NAME + ".getFormDataContentType(bodyString);" +
+          "                if (result.headers != null) {" +
+          "                  result.headers['Content-Type'] = result.headers['Content-Type'] == null ? formDataContentType : result.headers['Content-Type'];" +
+          "                } else {" +
+          "                  result.headers = { 'Content-Type': formDataContentType };" +
+          "                }" +
+          "              }" +
+          "            }" +
+          "            resource = result.url;" +
           "            if (init == null) {" +
           "              init = {};" +
           "            }" +
@@ -158,16 +107,18 @@ public class InterceptFetchRequestJS {
           "              init.method = result.method;" +
           "            }" +
           "            if (result.headers != null && Object.keys(result.headers).length > 0) {" +
-          "              init.headers = convertJsonToHeaders(result.headers);" +
+          "              init.headers = " + JavaScriptBridgeJS.JAVASCRIPT_UTIL_VAR_NAME + ".convertJsonToHeaders(result.headers);" +
           "            }" +
-          "            if (result.body != null && result.body.length > 0)   {" +
-          "              init.body = convertArrayIntBodyToUint8Array(result.body);" +
+          "            if (" + JavaScriptBridgeJS.JAVASCRIPT_UTIL_VAR_NAME + ".isString(result.body) || result.body == null) {" +
+          "              init.body = result.body;" +
+          "            } else if (result.body.length > 0) {" +
+          "              init.body = new Uint8Array(result.body);" +
           "            }" +
           "            if (result.mode != null && result.mode.length > 0) {" +
           "              init.mode = result.mode;" +
           "            }" +
           "            if (result.credentials != null) {" +
-          "              init.credentials = convertJsonToCredential(result.credentials);" +
+          "              init.credentials = " + JavaScriptBridgeJS.JAVASCRIPT_UTIL_VAR_NAME + ".convertJsonToCredential(result.credentials);" +
           "            }" +
           "            if (result.cache != null && result.cache.length > 0) {" +
           "              init.cache = result.cache;" +
diff --git a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/plugin_scripts_js/JavaScriptBridgeJS.java b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/plugin_scripts_js/JavaScriptBridgeJS.java
index 834789aa..4cd275d2 100644
--- a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/plugin_scripts_js/JavaScriptBridgeJS.java
+++ b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/plugin_scripts_js/JavaScriptBridgeJS.java
@@ -14,6 +14,203 @@ public class JavaScriptBridgeJS {
           true
   );
 
+  public static final String JAVASCRIPT_UTIL_VAR_NAME = "window." + JAVASCRIPT_BRIDGE_NAME + "._Util";
+
+  public static final String UTIL_JS_SOURCE = JAVASCRIPT_UTIL_VAR_NAME + " = {" +
+          "    support: {" +
+          "        searchParams: 'URLSearchParams' in window," +
+          "        iterable: 'Symbol' in window && 'iterator' in Symbol," +
+          "        blob:" +
+          "            'FileReader' in window &&" +
+          "            'Blob' in window &&" +
+          "            (function() {" +
+          "              try {" +
+          "                new Blob();" +
+          "                return true;" +
+          "              } catch (e) {" +
+          "                return false;" +
+          "              }" +
+          "            })()," +
+          "        formData: 'FormData' in window," +
+          "        arrayBuffer: 'ArrayBuffer' in window" +
+          "    }," +
+          "    isDataView: function(obj) {" +
+          "        return obj && DataView.prototype.isPrototypeOf(obj);" +
+          "    }," +
+          "    fileReaderReady: function(reader) {" +
+          "          return new Promise(function(resolve, reject) {" +
+          "                reader.onload = function() {" +
+          "                    resolve(reader.result);" +
+          "                };" +
+          "                reader.onerror = function() {" +
+          "                    reject(reader.error);" +
+          "                };" +
+          "          });" +
+          "    }," +
+          "    readBlobAsArrayBuffer: function(blob) {" +
+          "        var reader = new FileReader();" +
+          "        var promise = " + JAVASCRIPT_UTIL_VAR_NAME + ".fileReaderReady(reader);" +
+          "        reader.readAsArrayBuffer(blob);" +
+          "        return promise;" +
+          "    }," +
+          "    convertBodyToArrayBuffer: function(body) {" +
+          "        var viewClasses = [" +
+          "            '[object Int8Array]'," +
+          "            '[object Uint8Array]'," +
+          "            '[object Uint8ClampedArray]'," +
+          "            '[object Int16Array]'," +
+          "            '[object Uint16Array]'," +
+          "            '[object Int32Array]'," +
+          "            '[object Uint32Array]'," +
+          "            '[object Float32Array]'," +
+          "            '[object Float64Array]'" +
+          "        ];" +
+          "        var isArrayBufferView = null;" +
+          "        if (" + JAVASCRIPT_UTIL_VAR_NAME + ".support.arrayBuffer) {" +
+          "            isArrayBufferView =" +
+          "                ArrayBuffer.isView ||" +
+          "                function(obj) {" +
+          "                    return obj && viewClasses.indexOf(Object.prototype.toString.call(obj)) > -1;" +
+          "                };" +
+          "        }" +
+          "        var bodyUsed = false;" +
+          "        this._bodyInit = body;" +
+          "        if (!body) {" +
+          "            this._bodyText = '';" +
+          "        } else if (typeof body === 'string') {" +
+          "            this._bodyText = body;" +
+          "        } else if (" + JAVASCRIPT_UTIL_VAR_NAME + ".support.blob && Blob.prototype.isPrototypeOf(body)) {" +
+          "            this._bodyBlob = body;" +
+          "        } else if (" + JAVASCRIPT_UTIL_VAR_NAME + ".support.formData && FormData.prototype.isPrototypeOf(body)) {" +
+          "            this._bodyFormData = body;" +
+          "        } else if (" + JAVASCRIPT_UTIL_VAR_NAME + ".support.searchParams && URLSearchParams.prototype.isPrototypeOf(body)) {" +
+          "            this._bodyText = body.toString();" +
+          "        } else if (" + JAVASCRIPT_UTIL_VAR_NAME + ".support.arrayBuffer && " + JAVASCRIPT_UTIL_VAR_NAME + ".support.blob && " + JAVASCRIPT_UTIL_VAR_NAME + ".isDataView(body)) {" +
+          "            this._bodyArrayBuffer = bufferClone(body.buffer);" +
+          "            this._bodyInit = new Blob([this._bodyArrayBuffer]);" +
+          "        } else if (" + JAVASCRIPT_UTIL_VAR_NAME + ".support.arrayBuffer && (ArrayBuffer.prototype.isPrototypeOf(body) || isArrayBufferView(body))) {" +
+          "            this._bodyArrayBuffer = bufferClone(body);" +
+          "        } else {" +
+          "            this._bodyText = body = Object.prototype.toString.call(body);" +
+          "        }" +
+          "        this.blob = function () {" +
+          "            if (bodyUsed) {" +
+          "                return Promise.reject(new TypeError('Already read'));" +
+          "            }" +
+          "            bodyUsed = true;" +
+          "            if (this._bodyBlob) {" +
+          "                return Promise.resolve(this._bodyBlob);" +
+          "            } else if (this._bodyArrayBuffer) {" +
+          "                return Promise.resolve(new Blob([this._bodyArrayBuffer]));" +
+          "            } else if (this._bodyFormData) {" +
+          "                throw new Error('could not read FormData body as blob');" +
+          "            } else {" +
+          "                return Promise.resolve(new Blob([this._bodyText]));" +
+          "            }" +
+          "        };" +
+          "        if (this._bodyArrayBuffer) {" +
+          "            if (bodyUsed) {" +
+          "                return Promise.reject(new TypeError('Already read'));" +
+          "            }" +
+          "            bodyUsed = true;" +
+          "            if (ArrayBuffer.isView(this._bodyArrayBuffer)) {" +
+          "                return Promise.resolve(" +
+          "                  this._bodyArrayBuffer.buffer.slice(" +
+          "                    this._bodyArrayBuffer.byteOffset," +
+          "                    this._bodyArrayBuffer.byteOffset + this._bodyArrayBuffer.byteLength" +
+          "                  )" +
+          "                );" +
+          "            } else {" +
+          "                return Promise.resolve(this._bodyArrayBuffer);" +
+          "            }" +
+          "        }" +
+          "        return this.blob().then(" + JAVASCRIPT_UTIL_VAR_NAME + ".readBlobAsArrayBuffer);" +
+          "    }," +
+          "    isString: function(variable) {" +
+          "        return typeof variable === 'string' || variable instanceof String;" +
+          "    }," +
+          "    convertBodyRequest: function(body) {" +
+          "        if (body == null) {" +
+          "            return new Promise((resolve, reject) => resolve(null));" +
+          "        }" +
+          "        if (" + JAVASCRIPT_UTIL_VAR_NAME + ".isString(body) || (" + JAVASCRIPT_UTIL_VAR_NAME + ".support.searchParams && body instanceof URLSearchParams)) {" +
+          "            return new Promise((resolve, reject) => resolve(body.toString()));" +
+          "        }" +
+          "        if (window.Response != null) {" +
+          "            return new Response(body).arrayBuffer().then(function(arrayBuffer) {" +
+          "                return Array.from(new Uint8Array(arrayBuffer));" +
+          "            });" +
+          "        }" +
+          "        return " + JAVASCRIPT_UTIL_VAR_NAME + ".convertBodyToArrayBuffer(body).then(function(arrayBuffer) {" +
+          "            return Array.from(new Uint8Array(arrayBuffer));" +
+          "        });" +
+          "    }," +
+          "    arrayBufferToString: function(arrayBuffer) {" +
+          "        return String.fromCharCode.apply(String, arrayBuffer);" +
+          "    }," +
+          "    isBodyFormData: function(bodyString) {" +
+          "        return bodyString.indexOf('------WebKitFormBoundary') >= 0;" +
+          "    }," +
+          "    getFormDataContentType: function(bodyString) {" +
+          "        var boundary = bodyString.substr(2, 40);" +
+          "        return 'multipart/form-data; boundary=' + boundary;" +
+          "    }," +
+          "    convertHeadersToJson: function(headers) {" +
+          "        var headersObj = {};" +
+          "        for (var header of headers.keys()) {" +
+          "          var value = headers.get(header);" +
+          "          headersObj[header] = value;" +
+          "        }" +
+          "        return headersObj;" +
+          "    }," +
+          "    convertJsonToHeaders: function(headersJson) {" +
+          "        return new Headers(headersJson);" +
+          "    }," +
+          "    convertCredentialsToJson: function(credentials) {" +
+          "        var credentialsObj = {};" +
+          "        if (window.FederatedCredential != null && credentials instanceof FederatedCredential) {" +
+          "          credentialsObj.type = credentials.type;" +
+          "          credentialsObj.id = credentials.id;" +
+          "          credentialsObj.name = credentials.name;" +
+          "          credentialsObj.protocol = credentials.protocol;" +
+          "          credentialsObj.provider = credentials.provider;" +
+          "          credentialsObj.iconURL = credentials.iconURL;" +
+          "        } else if (window.PasswordCredential != null && credentials instanceof PasswordCredential) {" +
+          "          credentialsObj.type = credentials.type;" +
+          "          credentialsObj.id = credentials.id;" +
+          "          credentialsObj.name = credentials.name;" +
+          "          credentialsObj.password = credentials.password;" +
+          "          credentialsObj.iconURL = credentials.iconURL;" +
+          "        } else {" +
+          "          credentialsObj.type = 'default';" +
+          "          credentialsObj.value = credentials;" +
+          "        }" +
+          "        return credentialsObj;" +
+          "    }," +
+          "    convertJsonToCredential: function(credentialsJson) {" +
+          "        var credentials;" +
+          "        if (window.FederatedCredential != null && credentialsJson.type === 'federated') {" +
+          "          credentials = new FederatedCredential({" +
+          "            id: credentialsJson.id," +
+          "            name: credentialsJson.name," +
+          "            protocol: credentialsJson.protocol," +
+          "            provider: credentialsJson.provider," +
+          "            iconURL: credentialsJson.iconURL" +
+          "          });" +
+          "        } else if (window.PasswordCredential != null && credentialsJson.type === 'password') {" +
+          "          credentials = new PasswordCredential({" +
+          "            id: credentialsJson.id," +
+          "            name: credentialsJson.name," +
+          "            password: credentialsJson.password," +
+          "            iconURL: credentialsJson.iconURL" +
+          "          });" +
+          "        } else {" +
+          "          credentials = credentialsJson.value == null ? undefined : credentialsJson.value;" +
+          "        }" +
+          "        return credentials;" +
+          "    }" +
+          "};";
+
   public static final String JAVASCRIPT_BRIDGE_JS_SOURCE = "if (window.top == null || window.top === window) {" +
           "  window." + JAVASCRIPT_BRIDGE_NAME + ".callHandler = function() {" +
           "    var _callHandlerID = setTimeout(function(){});" +
@@ -30,8 +227,9 @@ public class JavaScriptBridgeJS {
           "    return new Promise(function(resolve, reject) {" +
           "      window.top." + JAVASCRIPT_BRIDGE_NAME + "[_callHandlerID] = resolve;" +
           "    });" +
-          "  };"+
-          "}";
+          "  };" +
+          "}" +
+          UTIL_JS_SOURCE;
 
   public static final String PLATFORM_READY_JS_SOURCE = "(function() {" +
           "  if ((window.top == null || window.top === window) && window." + JAVASCRIPT_BRIDGE_NAME + "._platformReady == null) {" +
diff --git a/example/integration_test/webview_flutter_test.dart b/example/integration_test/webview_flutter_test.dart
index 17d47e09..592a9f1a 100644
--- a/example/integration_test/webview_flutter_test.dart
+++ b/example/integration_test/webview_flutter_test.dart
@@ -1706,20 +1706,21 @@ void main() {
       skip: !Platform.isAndroid,
     );
 
-    testWidgets('intercept ajax request', (WidgetTester tester) async {
-      final Completer controllerCompleter = Completer<InAppWebViewController>();
-      final Completer shouldInterceptAjaxPostRequestCompleter =
-          Completer<void>();
-      final Completer<Map<String, dynamic>> onAjaxReadyStateChangeCompleter =
-          Completer<Map<String, dynamic>>();
-      final Completer<Map<String, dynamic>> onAjaxProgressCompleter =
-          Completer<Map<String, dynamic>>();
-      await tester.pumpWidget(
-        Directionality(
-          textDirection: TextDirection.ltr,
-          child: InAppWebView(
-            key: GlobalKey(),
-            initialData: InAppWebViewInitialData(data: """
+    group('intercept ajax request', () {
+      testWidgets('send string data', (WidgetTester tester) async {
+        final Completer controllerCompleter = Completer<InAppWebViewController>();
+        final Completer shouldInterceptAjaxPostRequestCompleter =
+        Completer<void>();
+        final Completer<Map<String, dynamic>> onAjaxReadyStateChangeCompleter =
+        Completer<Map<String, dynamic>>();
+        final Completer<Map<String, dynamic>> onAjaxProgressCompleter =
+        Completer<Map<String, dynamic>>();
+        await tester.pumpWidget(
+          Directionality(
+            textDirection: TextDirection.ltr,
+            child: InAppWebView(
+              key: GlobalKey(),
+              initialData: InAppWebViewInitialData(data: """
 <!doctype html>
 <html lang="en">
     <head>
@@ -1736,117 +1737,347 @@ void main() {
             xhttp.open("POST", "http://${environment["NODE_SERVER_IP"]}:8082/test-ajax-post");
             xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
             xhttp.send("firstname=Foo&lastname=Bar");
-
-            var xhttp2 = new XMLHttpRequest();
-            xhttp2.open("GET", "http://${environment["NODE_SERVER_IP"]}:8082/test-download-file");
-            xhttp2.send();
           });
         </script>
     </body>
 </html>
                     """),
-            initialOptions: InAppWebViewGroupOptions(
-                crossPlatform: InAppWebViewOptions(
-              clearCache: true,
-              useShouldInterceptAjaxRequest: true,
-            )),
-            onWebViewCreated: (controller) {
-              controllerCompleter.complete(controller);
-            },
-            shouldInterceptAjaxRequest: (controller, ajaxRequest) async {
-              if (ajaxRequest.url!.toString().endsWith("/test-ajax-post")) {
+              initialOptions: InAppWebViewGroupOptions(
+                  crossPlatform: InAppWebViewOptions(
+                    clearCache: true,
+                    useShouldInterceptAjaxRequest: true,
+                  )),
+              onWebViewCreated: (controller) {
+                controllerCompleter.complete(controller);
+              },
+              shouldInterceptAjaxRequest: (controller, ajaxRequest) async {
+                expect(ajaxRequest.data, "firstname=Foo&lastname=Bar");
+
                 ajaxRequest.responseType = 'json';
                 ajaxRequest.data = "firstname=Foo2&lastname=Bar2";
                 shouldInterceptAjaxPostRequestCompleter.complete(controller);
-              }
-              return ajaxRequest;
-            },
-            onAjaxReadyStateChange: (controller, ajaxRequest) async {
-              if (ajaxRequest.readyState == AjaxRequestReadyState.DONE &&
-                  ajaxRequest.status == 200 &&
-                  ajaxRequest.url!.toString().endsWith("/test-ajax-post")) {
-                Map<String, dynamic> res = ajaxRequest.response;
-                onAjaxReadyStateChangeCompleter.complete(res);
-              }
-              return AjaxRequestAction.PROCEED;
-            },
-            onAjaxProgress: (controller, ajaxRequest) async {
-              if (ajaxRequest.event!.type == AjaxRequestEventType.LOAD &&
-                  ajaxRequest.url!.toString().endsWith("/test-ajax-post")) {
-                Map<String, dynamic> res = ajaxRequest.response;
-                onAjaxProgressCompleter.complete(res);
-              }
-              return AjaxRequestAction.PROCEED;
-            },
+                return ajaxRequest;
+              },
+              onAjaxReadyStateChange: (controller, ajaxRequest) async {
+                if (ajaxRequest.readyState == AjaxRequestReadyState.DONE &&
+                    ajaxRequest.status == 200) {
+                  Map<String, dynamic> res = ajaxRequest.response;
+                  onAjaxReadyStateChangeCompleter.complete(res);
+                }
+                return AjaxRequestAction.PROCEED;
+              },
+              onAjaxProgress: (controller, ajaxRequest) async {
+                if (ajaxRequest.event!.type == AjaxRequestEventType.LOAD) {
+                  Map<String, dynamic> res = ajaxRequest.response;
+                  onAjaxProgressCompleter.complete(res);
+                }
+                return AjaxRequestAction.PROCEED;
+              },
+            ),
           ),
-        ),
-      );
+        );
 
-      await shouldInterceptAjaxPostRequestCompleter.future;
-      final Map<String, dynamic> onAjaxReadyStateChangeValue =
-          await onAjaxReadyStateChangeCompleter.future;
-      final Map<String, dynamic> onAjaxProgressValue =
-          await onAjaxProgressCompleter.future;
+        await shouldInterceptAjaxPostRequestCompleter.future;
+        final Map<String, dynamic> onAjaxReadyStateChangeValue =
+        await onAjaxReadyStateChangeCompleter.future;
+        final Map<String, dynamic> onAjaxProgressValue =
+        await onAjaxProgressCompleter.future;
 
-      expect(
-          mapEquals(onAjaxReadyStateChangeValue,
-              {'firstname': 'Foo2', 'lastname': 'Bar2'}),
-          true);
-      expect(
-          mapEquals(
-              onAjaxProgressValue, {'firstname': 'Foo2', 'lastname': 'Bar2'}),
-          true);
+        expect(
+            mapEquals(onAjaxReadyStateChangeValue,
+                {'firstname': 'Foo2', 'lastname': 'Bar2'}),
+            true);
+        expect(
+            mapEquals(
+                onAjaxProgressValue, {'firstname': 'Foo2', 'lastname': 'Bar2'}),
+            true);
+      });
+
+      testWidgets('send json data', (WidgetTester tester) async {
+        final Completer controllerCompleter = Completer<InAppWebViewController>();
+        final Completer shouldInterceptAjaxPostRequestCompleter =
+        Completer<void>();
+        final Completer<Map<String, dynamic>> onAjaxReadyStateChangeCompleter =
+        Completer<Map<String, dynamic>>();
+        final Completer<Map<String, dynamic>> onAjaxProgressCompleter =
+        Completer<Map<String, dynamic>>();
+        await tester.pumpWidget(
+          Directionality(
+            textDirection: TextDirection.ltr,
+            child: InAppWebView(
+              key: GlobalKey(),
+              initialData: InAppWebViewInitialData(data: """
+<!doctype html>
+<html lang="en">
+    <head>
+        <meta charset="UTF-8">
+        <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
+        <meta http-equiv="X-UA-Compatible" content="ie=edge">
+        <title>InAppWebViewAjaxTest</title>
+    </head>
+    <body>
+        <h1>InAppWebViewAjaxTest</h1>
+        <script>
+          window.addEventListener('flutterInAppWebViewPlatformReady', function(event) {
+            var jsonData = {
+              firstname: 'Foo',
+              lastname: 'Bar'
+            };
+            var xhttp = new XMLHttpRequest();
+            xhttp.open("POST", "http://${environment["NODE_SERVER_IP"]}:8082/test-ajax-post");
+            xhttp.setRequestHeader("Content-type", "application/json");
+            xhttp.send(JSON.stringify(jsonData));
+          });
+        </script>
+    </body>
+</html>
+                    """),
+              initialOptions: InAppWebViewGroupOptions(
+                  crossPlatform: InAppWebViewOptions(
+                    clearCache: true,
+                    useShouldInterceptAjaxRequest: true,
+                  )),
+              onWebViewCreated: (controller) {
+                controllerCompleter.complete(controller);
+              },
+              shouldInterceptAjaxRequest: (controller, ajaxRequest) async {
+                expect(ajaxRequest.data, '{"firstname":"Foo","lastname":"Bar"}');
+
+                ajaxRequest.responseType = 'json';
+                ajaxRequest.data = "{'firstname': 'Foo2', 'lastname': 'Bar2'}";
+                shouldInterceptAjaxPostRequestCompleter.complete(controller);
+                return ajaxRequest;
+              },
+              onAjaxReadyStateChange: (controller, ajaxRequest) async {
+                if (ajaxRequest.readyState == AjaxRequestReadyState.DONE &&
+                    ajaxRequest.status == 200) {
+                  Map<String, dynamic> res = ajaxRequest.response;
+                  onAjaxReadyStateChangeCompleter.complete(res);
+                }
+                return AjaxRequestAction.PROCEED;
+              },
+              onAjaxProgress: (controller, ajaxRequest) async {
+                if (ajaxRequest.event!.type == AjaxRequestEventType.LOAD) {
+                  Map<String, dynamic> res = ajaxRequest.response;
+                  onAjaxProgressCompleter.complete(res);
+                }
+                return AjaxRequestAction.PROCEED;
+              },
+            ),
+          ),
+        );
+
+        await shouldInterceptAjaxPostRequestCompleter.future;
+        final Map<String, dynamic> onAjaxReadyStateChangeValue =
+        await onAjaxReadyStateChangeCompleter.future;
+        final Map<String, dynamic> onAjaxProgressValue =
+        await onAjaxProgressCompleter.future;
+
+        expect(
+            mapEquals(onAjaxReadyStateChangeValue,
+                {'firstname': 'Foo2', 'lastname': 'Bar2'}),
+            true);
+        expect(
+            mapEquals(
+                onAjaxProgressValue, {'firstname': 'Foo2', 'lastname': 'Bar2'}),
+            true);
+      });
+
+      testWidgets('send URLSearchParams data', (WidgetTester tester) async {
+        final Completer controllerCompleter = Completer<InAppWebViewController>();
+        final Completer shouldInterceptAjaxPostRequestCompleter =
+        Completer<void>();
+        final Completer<Map<String, dynamic>> onAjaxReadyStateChangeCompleter =
+        Completer<Map<String, dynamic>>();
+        final Completer<Map<String, dynamic>> onAjaxProgressCompleter =
+        Completer<Map<String, dynamic>>();
+        await tester.pumpWidget(
+          Directionality(
+            textDirection: TextDirection.ltr,
+            child: InAppWebView(
+              key: GlobalKey(),
+              initialData: InAppWebViewInitialData(data: """
+<!doctype html>
+<html lang="en">
+    <head>
+        <meta charset="UTF-8">
+        <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
+        <meta http-equiv="X-UA-Compatible" content="ie=edge">
+        <title>InAppWebViewAjaxTest</title>
+    </head>
+    <body>
+        <h1>InAppWebViewAjaxTest</h1>
+        <script>
+          window.addEventListener('flutterInAppWebViewPlatformReady', function(event) {
+            var paramsString = "firstname=Foo&lastname=Bar";
+            var searchParams = new URLSearchParams(paramsString);
+            var xhttp = new XMLHttpRequest();
+            xhttp.open("POST", "http://${environment["NODE_SERVER_IP"]}:8082/test-ajax-post");
+            xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
+            xhttp.send(searchParams);
+          });
+        </script>
+    </body>
+</html>
+                    """),
+              initialOptions: InAppWebViewGroupOptions(
+                  crossPlatform: InAppWebViewOptions(
+                    clearCache: true,
+                    useShouldInterceptAjaxRequest: true,
+                  )),
+              onWebViewCreated: (controller) {
+                controllerCompleter.complete(controller);
+              },
+              shouldInterceptAjaxRequest: (controller, ajaxRequest) async {
+                expect(ajaxRequest.data, "firstname=Foo&lastname=Bar");
+
+                ajaxRequest.responseType = 'json';
+                ajaxRequest.data = "firstname=Foo2&lastname=Bar2";
+                shouldInterceptAjaxPostRequestCompleter.complete(controller);
+                return ajaxRequest;
+              },
+              onAjaxReadyStateChange: (controller, ajaxRequest) async {
+                if (ajaxRequest.readyState == AjaxRequestReadyState.DONE &&
+                    ajaxRequest.status == 200) {
+                  Map<String, dynamic> res = ajaxRequest.response;
+                  onAjaxReadyStateChangeCompleter.complete(res);
+                }
+                return AjaxRequestAction.PROCEED;
+              },
+              onAjaxProgress: (controller, ajaxRequest) async {
+                if (ajaxRequest.event!.type == AjaxRequestEventType.LOAD) {
+                  Map<String, dynamic> res = ajaxRequest.response;
+                  onAjaxProgressCompleter.complete(res);
+                }
+                return AjaxRequestAction.PROCEED;
+              },
+            ),
+          ),
+        );
+
+        await shouldInterceptAjaxPostRequestCompleter.future;
+        final Map<String, dynamic> onAjaxReadyStateChangeValue =
+        await onAjaxReadyStateChangeCompleter.future;
+        final Map<String, dynamic> onAjaxProgressValue =
+        await onAjaxProgressCompleter.future;
+
+        expect(
+            mapEquals(onAjaxReadyStateChangeValue,
+                {'firstname': 'Foo2', 'lastname': 'Bar2'}),
+            true);
+        expect(
+            mapEquals(
+                onAjaxProgressValue, {'firstname': 'Foo2', 'lastname': 'Bar2'}),
+            true);
+      });
+
+      testWidgets('send FormData', (WidgetTester tester) async {
+        final Completer controllerCompleter = Completer<InAppWebViewController>();
+        final Completer shouldInterceptAjaxPostRequestCompleter =
+        Completer<void>();
+        final Completer<Map<String, dynamic>> onAjaxReadyStateChangeCompleter =
+        Completer<Map<String, dynamic>>();
+        final Completer<Map<String, dynamic>> onAjaxProgressCompleter =
+        Completer<Map<String, dynamic>>();
+        await tester.pumpWidget(
+          Directionality(
+            textDirection: TextDirection.ltr,
+            child: InAppWebView(
+              key: GlobalKey(),
+              initialData: InAppWebViewInitialData(data: """
+<!doctype html>
+<html lang="en">
+    <head>
+        <meta charset="UTF-8">
+        <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
+        <meta http-equiv="X-UA-Compatible" content="ie=edge">
+        <title>InAppWebViewAjaxTest</title>
+    </head>
+    <body>
+        <h1>InAppWebViewAjaxTest</h1>
+        <script>
+          window.addEventListener('flutterInAppWebViewPlatformReady', function(event) {
+            var formData = new FormData();
+            formData.append('firstname', 'Foo');
+            formData.append('lastname', 'Bar');
+            var xhttp = new XMLHttpRequest();
+            xhttp.open("POST", "http://${environment["NODE_SERVER_IP"]}:8082/test-ajax-post");
+            xhttp.send(formData);
+          });
+        </script>
+    </body>
+</html>
+                    """),
+              initialOptions: InAppWebViewGroupOptions(
+                  crossPlatform: InAppWebViewOptions(
+                    clearCache: true,
+                    useShouldInterceptAjaxRequest: true,
+                  )),
+              onWebViewCreated: (controller) {
+                controllerCompleter.complete(controller);
+              },
+              shouldInterceptAjaxRequest: (controller, ajaxRequest) async {
+                expect(ajaxRequest.data, isNotNull);
+
+                var body = ajaxRequest.data.cast<int>();
+                var bodyString = String.fromCharCodes(body);
+                expect(bodyString.indexOf("WebKitFormBoundary") >= 0, true);
+
+                ajaxRequest.data = utf8.encode(bodyString.replaceFirst("Foo", "Foo2").replaceFirst("Bar", "Bar2"));
+                ajaxRequest.responseType = 'json';
+                shouldInterceptAjaxPostRequestCompleter.complete(controller);
+                return ajaxRequest;
+              },
+              onAjaxReadyStateChange: (controller, ajaxRequest) async {
+                if (ajaxRequest.readyState == AjaxRequestReadyState.DONE &&
+                    ajaxRequest.status == 200) {
+                  Map<String, dynamic> res = ajaxRequest.response;
+                  onAjaxReadyStateChangeCompleter.complete(res);
+                }
+                return AjaxRequestAction.PROCEED;
+              },
+              onAjaxProgress: (controller, ajaxRequest) async {
+                if (ajaxRequest.event!.type == AjaxRequestEventType.LOAD) {
+                  Map<String, dynamic> res = ajaxRequest.response;
+                  onAjaxProgressCompleter.complete(res);
+                }
+                return AjaxRequestAction.PROCEED;
+              },
+            ),
+          ),
+        );
+
+        await shouldInterceptAjaxPostRequestCompleter.future;
+        final Map<String, dynamic> onAjaxReadyStateChangeValue =
+        await onAjaxReadyStateChangeCompleter.future;
+        final Map<String, dynamic> onAjaxProgressValue =
+        await onAjaxProgressCompleter.future;
+
+        expect(
+            mapEquals(onAjaxReadyStateChangeValue,
+                {'firstname': 'Foo2', 'lastname': 'Bar2'}),
+            true);
+        expect(
+            mapEquals(
+                onAjaxProgressValue, {'firstname': 'Foo2', 'lastname': 'Bar2'}),
+            true);
+      });
     });
 
-    testWidgets('Content Blocker', (WidgetTester tester) async {
-      final Completer controllerCompleter = Completer<InAppWebViewController>();
-      final Completer<void> pageLoaded = Completer<void>();
-      await tester.pumpWidget(
-        Directionality(
-          textDirection: TextDirection.ltr,
-          child: InAppWebView(
-            key: GlobalKey(),
-            initialUrlRequest:
-                URLRequest(url: Uri.parse('https://flutter.dev/')),
-            onWebViewCreated: (controller) {
-              controllerCompleter.complete(controller);
-            },
-            initialOptions: InAppWebViewGroupOptions(
-                crossPlatform:
-                    InAppWebViewOptions(clearCache: true, contentBlockers: [
-              ContentBlocker(
-                  trigger:
-                      ContentBlockerTrigger(urlFilter: ".*", resourceType: [
-                    ContentBlockerTriggerResourceType.IMAGE,
-                    ContentBlockerTriggerResourceType.STYLE_SHEET
-                  ], ifTopUrl: [
-                    "https://flutter.dev/"
-                  ]),
-                  action: ContentBlockerAction(
-                      type: ContentBlockerActionType.BLOCK))
-            ])),
-            onLoadStop: (controller, url) {
-              pageLoaded.complete();
-            },
-          ),
-        ),
-      );
-      await expectLater(pageLoaded.future, completes);
-    });
-
-    testWidgets('intercept fetch request', (WidgetTester tester) async {
-      final Completer controllerCompleter = Completer<InAppWebViewController>();
-      final Completer<String> fetchGetCompleter = Completer<String>();
-      final Completer<Map<String, dynamic>> fetchPostCompleter =
-          Completer<Map<String, dynamic>>();
-      final Completer<void> shouldInterceptFetchPostRequestCompleter =
-          Completer<void>();
-      await tester.pumpWidget(
-        Directionality(
-          textDirection: TextDirection.ltr,
-          child: InAppWebView(
-            key: GlobalKey(),
-            initialData: InAppWebViewInitialData(data: """
+    group('intercept fetch request', () {
+      testWidgets('send string data', (WidgetTester tester) async {
+        final Completer controllerCompleter = Completer<InAppWebViewController>();
+        final Completer<String> fetchGetCompleter = Completer<String>();
+        final Completer<Map<String, dynamic>> fetchPostCompleter =
+        Completer<Map<String, dynamic>>();
+        final Completer<void> shouldInterceptFetchPostRequestCompleter =
+        Completer<void>();
+        await tester.pumpWidget(
+          Directionality(
+            textDirection: TextDirection.ltr,
+            child: InAppWebView(
+              key: GlobalKey(),
+              initialData: InAppWebViewInitialData(data: """
 <!doctype html>
 <html lang="en">
     <head>
@@ -1859,21 +2090,12 @@ void main() {
         <h1>InAppWebViewFetchTest</h1>
         <script>
           window.addEventListener('flutterInAppWebViewPlatformReady', function(event) {
-            fetch(new Request("http://${environment["NODE_SERVER_IP"]}:8082/test-download-file")).then(function(response) {
-                window.flutter_inappwebview.callHandler('fetchGet', response.status);
-            }).catch(function(error) {
-                window.flutter_inappwebview.callHandler('fetchGet', "ERROR: " + error);
-            });
-
             fetch("http://${environment["NODE_SERVER_IP"]}:8082/test-ajax-post", {
                 method: 'POST',
-                body: JSON.stringify({
-                    firstname: 'Foo',
-                    lastname: 'Bar'
-                }),
                 headers: {
-                  'Content-Type': 'application/json'
-                }
+                  'Content-Type': 'application/x-www-form-urlencoded'
+                },
+                body: "firstname=Foo&lastname=Bar"
             }).then(function(response) {
                 response.json().then(function(value) {
                   window.flutter_inappwebview.callHandler('fetchPost', value);
@@ -1888,52 +2110,338 @@ void main() {
     </body>
 </html>
                     """),
-            initialOptions: InAppWebViewGroupOptions(
-                crossPlatform: InAppWebViewOptions(
-              clearCache: true,
-              useShouldInterceptFetchRequest: true,
-            )),
+              initialOptions: InAppWebViewGroupOptions(
+                  crossPlatform: InAppWebViewOptions(
+                    clearCache: true,
+                    useShouldInterceptFetchRequest: true,
+                  )),
+              onWebViewCreated: (controller) {
+                controllerCompleter.complete(controller);
+
+                controller.addJavaScriptHandler(
+                    handlerName: "fetchPost",
+                    callback: (args) {
+                      fetchPostCompleter
+                          .complete(args[0] as Map<String, dynamic>);
+                    });
+              },
+              shouldInterceptFetchRequest: (controller, fetchRequest) async {
+                expect(fetchRequest.body, "firstname=Foo&lastname=Bar");
+
+                fetchRequest.body = "firstname=Foo2&lastname=Bar2";
+                shouldInterceptFetchPostRequestCompleter.complete();
+                return fetchRequest;
+              },
+            ),
+          ),
+        );
+
+        var fetchGetCompleterValue = await fetchGetCompleter.future;
+        expect(fetchGetCompleterValue, '200');
+
+        await shouldInterceptFetchPostRequestCompleter.future;
+        var fetchPostCompleterValue = await fetchPostCompleter.future;
+
+        expect(
+            mapEquals(fetchPostCompleterValue,
+                {'firstname': 'Foo2', 'lastname': 'Bar2'}),
+            true);
+      });
+
+      testWidgets('send json data', (WidgetTester tester) async {
+        final Completer controllerCompleter = Completer<InAppWebViewController>();
+        final Completer<String> fetchGetCompleter = Completer<String>();
+        final Completer<Map<String, dynamic>> fetchPostCompleter =
+        Completer<Map<String, dynamic>>();
+        final Completer<void> shouldInterceptFetchPostRequestCompleter =
+        Completer<void>();
+        await tester.pumpWidget(
+          Directionality(
+            textDirection: TextDirection.ltr,
+            child: InAppWebView(
+              key: GlobalKey(),
+              initialData: InAppWebViewInitialData(data: """
+<!doctype html>
+<html lang="en">
+    <head>
+        <meta charset="UTF-8">
+        <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
+        <meta http-equiv="X-UA-Compatible" content="ie=edge">
+        <title>InAppWebViewFetchTest</title>
+    </head>
+    <body>
+        <h1>InAppWebViewFetchTest</h1>
+        <script>
+          window.addEventListener('flutterInAppWebViewPlatformReady', function(event) {
+            var jsonData = {
+              firstname: 'Foo',
+              lastname: 'Bar'
+            };
+            fetch("http://${environment["NODE_SERVER_IP"]}:8082/test-ajax-post", {
+                method: 'POST',
+                headers: {
+                  'Content-Type': 'application/json'
+                },
+                body: JSON.stringify(jsonData)
+            }).then(function(response) {
+                response.json().then(function(value) {
+                  window.flutter_inappwebview.callHandler('fetchPost', value);
+                }).catch(function(error) {
+                    window.flutter_inappwebview.callHandler('fetchPost', "ERROR: " + error);
+                });
+            }).catch(function(error) {
+                window.flutter_inappwebview.callHandler('fetchPost', "ERROR: " + error);
+            });
+          });
+        </script>
+    </body>
+</html>
+                    """),
+              initialOptions: InAppWebViewGroupOptions(
+                  crossPlatform: InAppWebViewOptions(
+                    clearCache: true,
+                    useShouldInterceptFetchRequest: true,
+                  )),
+              onWebViewCreated: (controller) {
+                controllerCompleter.complete(controller);
+
+                controller.addJavaScriptHandler(
+                    handlerName: "fetchPost",
+                    callback: (args) {
+                      fetchPostCompleter
+                          .complete(args[0] as Map<String, dynamic>);
+                    });
+              },
+              shouldInterceptFetchRequest: (controller, fetchRequest) async {
+                expect(fetchRequest.body, '{"firstname":"Foo","lastname":"Bar"}');
+
+                fetchRequest.body = "{'firstname': 'Foo2', 'lastname': 'Bar2'}";
+                shouldInterceptFetchPostRequestCompleter.complete();
+                return fetchRequest;
+              },
+            ),
+          ),
+        );
+
+        var fetchGetCompleterValue = await fetchGetCompleter.future;
+        expect(fetchGetCompleterValue, '200');
+
+        await shouldInterceptFetchPostRequestCompleter.future;
+        var fetchPostCompleterValue = await fetchPostCompleter.future;
+
+        expect(
+            mapEquals(fetchPostCompleterValue,
+                {'firstname': 'Foo2', 'lastname': 'Bar2'}),
+            true);
+      });
+
+      testWidgets('send URLSearchParams data', (WidgetTester tester) async {
+        final Completer controllerCompleter = Completer<InAppWebViewController>();
+        final Completer<String> fetchGetCompleter = Completer<String>();
+        final Completer<Map<String, dynamic>> fetchPostCompleter =
+        Completer<Map<String, dynamic>>();
+        final Completer<void> shouldInterceptFetchPostRequestCompleter =
+        Completer<void>();
+        await tester.pumpWidget(
+          Directionality(
+            textDirection: TextDirection.ltr,
+            child: InAppWebView(
+              key: GlobalKey(),
+              initialData: InAppWebViewInitialData(data: """
+<!doctype html>
+<html lang="en">
+    <head>
+        <meta charset="UTF-8">
+        <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
+        <meta http-equiv="X-UA-Compatible" content="ie=edge">
+        <title>InAppWebViewFetchTest</title>
+    </head>
+    <body>
+        <h1>InAppWebViewFetchTest</h1>
+        <script>
+          window.addEventListener('flutterInAppWebViewPlatformReady', function(event) {
+            var paramsString = "firstname=Foo&lastname=Bar";
+            var searchParams = new URLSearchParams(paramsString);
+            fetch("http://${environment["NODE_SERVER_IP"]}:8082/test-ajax-post", {
+                method: 'POST',
+                headers: {
+                  'Content-Type': 'application/x-www-form-urlencoded'
+                },
+                body: searchParams
+            }).then(function(response) {
+                response.json().then(function(value) {
+                  window.flutter_inappwebview.callHandler('fetchPost', value);
+                }).catch(function(error) {
+                    window.flutter_inappwebview.callHandler('fetchPost', "ERROR: " + error);
+                });
+            }).catch(function(error) {
+                window.flutter_inappwebview.callHandler('fetchPost', "ERROR: " + error);
+            });
+          });
+        </script>
+    </body>
+</html>
+                    """),
+              initialOptions: InAppWebViewGroupOptions(
+                  crossPlatform: InAppWebViewOptions(
+                    clearCache: true,
+                    useShouldInterceptFetchRequest: true,
+                  )),
+              onWebViewCreated: (controller) {
+                controllerCompleter.complete(controller);
+
+                controller.addJavaScriptHandler(
+                    handlerName: "fetchPost",
+                    callback: (args) {
+                      fetchPostCompleter
+                          .complete(args[0] as Map<String, dynamic>);
+                    });
+              },
+              shouldInterceptFetchRequest: (controller, fetchRequest) async {
+                expect(fetchRequest.body, "firstname=Foo&lastname=Bar");
+
+                fetchRequest.body = "firstname=Foo2&lastname=Bar2";
+                shouldInterceptFetchPostRequestCompleter.complete();
+                return fetchRequest;
+              },
+            ),
+          ),
+        );
+
+        var fetchGetCompleterValue = await fetchGetCompleter.future;
+        expect(fetchGetCompleterValue, '200');
+
+        await shouldInterceptFetchPostRequestCompleter.future;
+        var fetchPostCompleterValue = await fetchPostCompleter.future;
+
+        expect(
+            mapEquals(fetchPostCompleterValue,
+                {'firstname': 'Foo2', 'lastname': 'Bar2'}),
+            true);
+      });
+
+      testWidgets('send FormData', (WidgetTester tester) async {
+        final Completer controllerCompleter = Completer<InAppWebViewController>();
+        final Completer<String> fetchGetCompleter = Completer<String>();
+        final Completer<Map<String, dynamic>> fetchPostCompleter =
+        Completer<Map<String, dynamic>>();
+        final Completer<void> shouldInterceptFetchPostRequestCompleter =
+        Completer<void>();
+        await tester.pumpWidget(
+          Directionality(
+            textDirection: TextDirection.ltr,
+            child: InAppWebView(
+              key: GlobalKey(),
+              initialData: InAppWebViewInitialData(data: """
+<!doctype html>
+<html lang="en">
+    <head>
+        <meta charset="UTF-8">
+        <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
+        <meta http-equiv="X-UA-Compatible" content="ie=edge">
+        <title>InAppWebViewFetchTest</title>
+    </head>
+    <body>
+        <h1>InAppWebViewFetchTest</h1>
+        <script>
+          window.addEventListener('flutterInAppWebViewPlatformReady', function(event) {
+            var formData = new FormData();
+            formData.append('firstname', 'Foo');
+            formData.append('lastname', 'Bar');
+            fetch("http://${environment["NODE_SERVER_IP"]}:8082/test-ajax-post", {
+                method: 'POST',
+                body: formData
+            }).then(function(response) {
+                response.json().then(function(value) {
+                  window.flutter_inappwebview.callHandler('fetchPost', value);
+                }).catch(function(error) {
+                    window.flutter_inappwebview.callHandler('fetchPost', "ERROR: " + error);
+                });
+            }).catch(function(error) {
+                window.flutter_inappwebview.callHandler('fetchPost', "ERROR: " + error);
+            });
+          });
+        </script>
+    </body>
+</html>
+                    """),
+              initialOptions: InAppWebViewGroupOptions(
+                  crossPlatform: InAppWebViewOptions(
+                    clearCache: true,
+                    useShouldInterceptFetchRequest: true,
+                  )),
+              onWebViewCreated: (controller) {
+                controllerCompleter.complete(controller);
+
+                controller.addJavaScriptHandler(
+                    handlerName: "fetchPost",
+                    callback: (args) {
+                      fetchPostCompleter
+                          .complete(args[0] as Map<String, dynamic>);
+                    });
+              },
+              shouldInterceptFetchRequest: (controller, fetchRequest) async {
+                expect(fetchRequest.body, isNotNull);
+
+                var body = fetchRequest.body.cast<int>();
+                var bodyString = String.fromCharCodes(body);
+                expect(bodyString.indexOf("WebKitFormBoundary") >= 0, true);
+
+                fetchRequest.body = utf8.encode(bodyString.replaceFirst("Foo", "Foo2").replaceFirst("Bar", "Bar2"));
+                shouldInterceptFetchPostRequestCompleter.complete();
+                return fetchRequest;
+              },
+            ),
+          ),
+        );
+
+        var fetchGetCompleterValue = await fetchGetCompleter.future;
+        expect(fetchGetCompleterValue, '200');
+
+        await shouldInterceptFetchPostRequestCompleter.future;
+        var fetchPostCompleterValue = await fetchPostCompleter.future;
+
+        expect(
+            mapEquals(fetchPostCompleterValue,
+                {'firstname': 'Foo2', 'lastname': 'Bar2'}),
+            true);
+      });
+    });
+
+    testWidgets('Content Blocker', (WidgetTester tester) async {
+      final Completer controllerCompleter = Completer<InAppWebViewController>();
+      final Completer<void> pageLoaded = Completer<void>();
+      await tester.pumpWidget(
+        Directionality(
+          textDirection: TextDirection.ltr,
+          child: InAppWebView(
+            key: GlobalKey(),
+            initialUrlRequest:
+            URLRequest(url: Uri.parse('https://flutter.dev/')),
             onWebViewCreated: (controller) {
               controllerCompleter.complete(controller);
-
-              controller.addJavaScriptHandler(
-                  handlerName: "fetchGet",
-                  callback: (args) {
-                    fetchGetCompleter.complete(args[0].toString());
-                  });
-
-              controller.addJavaScriptHandler(
-                  handlerName: "fetchPost",
-                  callback: (args) {
-                    fetchPostCompleter
-                        .complete(args[0] as Map<String, dynamic>);
-                  });
             },
-            shouldInterceptFetchRequest: (controller, fetchRequest) async {
-              if (fetchRequest.url!.toString().endsWith("/test-ajax-post")) {
-                fetchRequest.body = utf8.encode("""{
-                "firstname": "Foo2",
-                "lastname": "Bar2"
-              }
-              """) as Uint8List;
-                shouldInterceptFetchPostRequestCompleter.complete();
-              }
-              return fetchRequest;
+            initialOptions: InAppWebViewGroupOptions(
+                crossPlatform:
+                InAppWebViewOptions(clearCache: true, contentBlockers: [
+                  ContentBlocker(
+                      trigger:
+                      ContentBlockerTrigger(urlFilter: ".*", resourceType: [
+                        ContentBlockerTriggerResourceType.IMAGE,
+                        ContentBlockerTriggerResourceType.STYLE_SHEET
+                      ], ifTopUrl: [
+                        "https://flutter.dev/"
+                      ]),
+                      action: ContentBlockerAction(
+                          type: ContentBlockerActionType.BLOCK))
+                ])),
+            onLoadStop: (controller, url) {
+              pageLoaded.complete();
             },
           ),
         ),
       );
-
-      var fetchGetCompleterValue = await fetchGetCompleter.future;
-      expect(fetchGetCompleterValue, '200');
-
-      await shouldInterceptFetchPostRequestCompleter.future;
-      var fetchPostCompleterValue = await fetchPostCompleter.future;
-
-      expect(
-          mapEquals(fetchPostCompleterValue,
-              {'firstname': 'Foo2', 'lastname': 'Bar2'}),
-          true);
+      await expectLater(pageLoaded.future, completes);
     });
 
     testWidgets('Http Auth Credential Database', (WidgetTester tester) async {
@@ -5001,4 +5509,37 @@ setTimeout(function() {
       expect(chromeSafariBrowser.isOpened(), false);
     });
   });
+
+  group('InAppLocalhostServer', () {
+    final InAppLocalhostServer localhostServer = InAppLocalhostServer();
+
+    setUpAll(() async {
+      localhostServer.start();
+    });
+
+    testWidgets('load asset file', (WidgetTester tester) async {
+      final Completer controllerCompleter = Completer<InAppWebViewController>();
+      await tester.pumpWidget(
+        Directionality(
+          textDirection: TextDirection.ltr,
+          child: InAppWebView(
+            key: GlobalKey(),
+            initialUrlRequest:
+            URLRequest(url: Uri.parse('http://localhost:8080/test_assets/index.html')),
+            onWebViewCreated: (controller) {
+              controllerCompleter.complete(controller);
+            },
+          ),
+        ),
+      );
+      final InAppWebViewController controller =
+      await controllerCompleter.future;
+      final String? currentUrl = (await controller.getUrl())?.toString();
+      expect(currentUrl, 'http://localhost:8080/test_assets/index.html');
+    });
+
+    tearDownAll(() async {
+      localhostServer.close();
+    });
+  });
 }
diff --git a/ios/Classes/PluginScriptsJS/InterceptAjaxRequestJS.swift b/ios/Classes/PluginScriptsJS/InterceptAjaxRequestJS.swift
index b51ca464..4ec05183 100644
--- a/ios/Classes/PluginScriptsJS/InterceptAjaxRequestJS.swift
+++ b/ios/Classes/PluginScriptsJS/InterceptAjaxRequestJS.swift
@@ -183,46 +183,65 @@ let INTERCEPT_AJAX_REQUEST_JS_SOURCE = """
       this.addEventListener('error', handleEvent);
       this.addEventListener('abort', handleEvent);
       this.addEventListener('timeout', handleEvent);
-      var ajaxRequest = {
-        data: data,
-        method: this._flutter_inappwebview_method,
-        url: this._flutter_inappwebview_url,
-        isAsync: this._flutter_inappwebview_isAsync,
-        user: this._flutter_inappwebview_user,
-        password: this._flutter_inappwebview_password,
-        withCredentials: this.withCredentials,
-        headers: this._flutter_inappwebview_request_headers,
-        responseType: this.responseType
-      };
-      window.\(JAVASCRIPT_BRIDGE_NAME).callHandler('shouldInterceptAjaxRequest', ajaxRequest).then(function(result) {
-        if (result != null) {
-          switch (result.action) {
-            case 0:
-              self.abort();
-              return;
+      \(JAVASCRIPT_UTIL_VAR_NAME).convertBodyRequest(data).then(function(data) {
+          var ajaxRequest = {
+            data: data,
+            method: self._flutter_inappwebview_method,
+            url: self._flutter_inappwebview_url,
+            isAsync: self._flutter_inappwebview_isAsync,
+            user: self._flutter_inappwebview_user,
+            password: self._flutter_inappwebview_password,
+            withCredentials: self.withCredentials,
+            headers: self._flutter_inappwebview_request_headers,
+            responseType: self.responseType
           };
-          data = result.data;
-          self.withCredentials = result.withCredentials;
-          if (result.responseType != null) {
-            self.responseType = result.responseType;
-          };
-          for (var header in result.headers) {
-            var value = result.headers[header];
-            var flutter_inappwebview_value = self._flutter_inappwebview_request_headers[header];
-            if (flutter_inappwebview_value == null) {
-              self._flutter_inappwebview_request_headers[header] = value;
-            } else {
-              self._flutter_inappwebview_request_headers[header] += ', ' + value;
+          window.\(JAVASCRIPT_BRIDGE_NAME).callHandler('shouldInterceptAjaxRequest', ajaxRequest).then(function(result) {
+            if (result != null) {
+              switch (result.action) {
+                case 0:
+                  self.abort();
+                  return;
+              };
+              if (result.data != null && !\(JAVASCRIPT_UTIL_VAR_NAME).isString(result.data) && result.data.length > 0) {
+                var bodyString = \(JAVASCRIPT_UTIL_VAR_NAME).arrayBufferToString(result.data);
+                if (\(JAVASCRIPT_UTIL_VAR_NAME).isBodyFormData(bodyString)) {
+                  var formDataContentType = \(JAVASCRIPT_UTIL_VAR_NAME).getFormDataContentType(bodyString);
+                  if (result.headers != null) {
+                    result.headers['Content-Type'] = result.headers['Content-Type'] == null ? formDataContentType : result.headers['Content-Type'];
+                  } else {
+                    result.headers = { 'Content-Type': formDataContentType };
+                  }
+                }
+              }
+              if (\(JAVASCRIPT_UTIL_VAR_NAME).isString(result.data) || result.data == null) {
+                data = result.data;
+              } else if (result.data.length > 0) {
+                data = new Uint8Array(result.data);
+              }
+              self.withCredentials = result.withCredentials;
+              if (result.responseType != null) {
+                self.responseType = result.responseType;
+              };
+              if (result.headers != null) {
+                for (var header in result.headers) {
+                  var value = result.headers[header];
+                  var flutter_inappwebview_value = self._flutter_inappwebview_request_headers[header];
+                  if (flutter_inappwebview_value == null) {
+                    self._flutter_inappwebview_request_headers[header] = value;
+                  } else {
+                    self._flutter_inappwebview_request_headers[header] += ', ' + value;
+                  }
+                  setRequestHeader.call(self, header, value);
+                };
+              }
+              if ((self._flutter_inappwebview_method != result.method && result.method != null) || (self._flutter_inappwebview_url != result.url && result.url != null)) {
+                self.abort();
+                self.open(result.method, result.url, result.isAsync, result.user, result.password);
+                return;
+              }
             }
-            setRequestHeader.call(self, header, value);
-          };
-          if ((self._flutter_inappwebview_method != result.method && result.method != null) || (self._flutter_inappwebview_url != result.url && result.url != null)) {
-            self.abort();
-            self.open(result.method, result.url, result.isAsync, result.user, result.password);
-            return;
-          }
-        }
-        send.call(self, data);
+            send.call(self, data);
+          });
       });
     } else {
       send.call(this, data);
diff --git a/ios/Classes/PluginScriptsJS/InterceptFetchRequestJS.swift b/ios/Classes/PluginScriptsJS/InterceptFetchRequestJS.swift
index 3fa45c3b..14539811 100644
--- a/ios/Classes/PluginScriptsJS/InterceptFetchRequestJS.swift
+++ b/ios/Classes/PluginScriptsJS/InterceptFetchRequestJS.swift
@@ -24,68 +24,6 @@ let INTERCEPT_FETCH_REQUEST_JS_SOURCE = """
   if (fetch == null) {
     return;
   }
-  function convertHeadersToJson(headers) {
-    var headersObj = {};
-    for (var header of headers.keys()) {
-      var value = headers.get(header);
-      headersObj[header] = value;
-    }
-    return headersObj;
-  }
-  function convertJsonToHeaders(headersJson) {
-    return new Headers(headersJson);
-  }
-  function convertBodyToArray(body) {
-    return new Response(body).arrayBuffer().then(function(arrayBuffer) {
-      var arr = Array.from(new Uint8Array(arrayBuffer));
-      return arr;
-    })
-  }
-  function convertArrayIntBodyToUint8Array(arrayIntBody) {
-    return new Uint8Array(arrayIntBody);
-  }
-  function convertCredentialsToJson(credentials) {
-    var credentialsObj = {};
-    if (window.FederatedCredential != null && credentials instanceof FederatedCredential) {
-      credentialsObj.type = credentials.type;
-      credentialsObj.id = credentials.id;
-      credentialsObj.name = credentials.name;
-      credentialsObj.protocol = credentials.protocol;
-      credentialsObj.provider = credentials.provider;
-      credentialsObj.iconURL = credentials.iconURL;
-    } else if (window.PasswordCredential != null && credentials instanceof PasswordCredential) {
-      credentialsObj.type = credentials.type;
-      credentialsObj.id = credentials.id;
-      credentialsObj.name = credentials.name;
-      credentialsObj.password = credentials.password;
-      credentialsObj.iconURL = credentials.iconURL;
-    } else {
-      credentialsObj.type = 'default';
-      credentialsObj.value = credentials;
-    }
-  }
-  function convertJsonToCredential(credentialsJson) {
-    var credentials;
-    if (window.FederatedCredential != null && credentialsJson.type === 'federated') {
-      credentials = new FederatedCredential({
-        id: credentialsJson.id,
-        name: credentialsJson.name,
-        protocol: credentialsJson.protocol,
-        provider: credentialsJson.provider,
-        iconURL: credentialsJson.iconURL
-      });
-    } else if (window.PasswordCredential != null && credentialsJson.type === 'password') {
-      credentials = new PasswordCredential({
-        id: credentialsJson.id,
-        name: credentialsJson.name,
-        password: credentialsJson.password,
-        iconURL: credentialsJson.iconURL
-      });
-    } else {
-      credentials = credentialsJson;
-    }
-    return credentials;
-  }
   window.fetch = async function(resource, init) {
     if (\(FLAG_VARIABLE_FOR_SHOULD_INTERCEPT_FETCH_REQUEST_JS_SOURCE) == null || \(FLAG_VARIABLE_FOR_SHOULD_INTERCEPT_FETCH_REQUEST_JS_SOURCE) == true) {
       var fetchRequest = {
@@ -116,7 +54,7 @@ let INTERCEPT_FETCH_REQUEST_JS_SOURCE = """
         fetchRequest.integrity = resource.integrity;
         fetchRequest.keepalive = resource.keepalive;
       } else {
-        fetchRequest.url = resource;
+        fetchRequest.url = resource != null ? resource.toString() : null;
         if (init != null) {
           fetchRequest.method = init.method;
           fetchRequest.headers = init.headers;
@@ -132,10 +70,10 @@ let INTERCEPT_FETCH_REQUEST_JS_SOURCE = """
         }
       }
       if (fetchRequest.headers instanceof Headers) {
-        fetchRequest.headers = convertHeadersToJson(fetchRequest.headers);
+        fetchRequest.headers = \(JAVASCRIPT_UTIL_VAR_NAME).convertHeadersToJson(fetchRequest.headers);
       }
-      fetchRequest.credentials = convertCredentialsToJson(fetchRequest.credentials);
-      return convertBodyToArray(fetchRequest.body).then(function(body) {
+      fetchRequest.credentials = \(JAVASCRIPT_UTIL_VAR_NAME).convertCredentialsToJson(fetchRequest.credentials);
+      return \(JAVASCRIPT_UTIL_VAR_NAME).convertBodyRequest(fetchRequest.body).then(function(body) {
         fetchRequest.body = body;
         return window.\(JAVASCRIPT_BRIDGE_NAME).callHandler('shouldInterceptFetchRequest', fetchRequest).then(function(result) {
           if (result != null) {
@@ -152,7 +90,18 @@ let INTERCEPT_FETCH_REQUEST_JS_SOURCE = """
                 controller.abort();
                 break;
             }
-            resource = (result.url != null) ? result.url : resource;
+            if (result.body != null && !\(JAVASCRIPT_UTIL_VAR_NAME).isString(result.body) && result.body.length > 0) {
+              var bodyString = \(JAVASCRIPT_UTIL_VAR_NAME).arrayBufferToString(result.body);
+              if (\(JAVASCRIPT_UTIL_VAR_NAME).isBodyFormData(bodyString)) {
+                var formDataContentType = \(JAVASCRIPT_UTIL_VAR_NAME).getFormDataContentType(bodyString);
+                if (result.headers != null) {
+                  result.headers['Content-Type'] = result.headers['Content-Type'] == null ? formDataContentType : result.headers['Content-Type'];
+                } else {
+                  result.headers = { 'Content-Type': formDataContentType };
+                }
+              }
+            }
+            resource = result.url;
             if (init == null) {
               init = {};
             }
@@ -160,16 +109,18 @@ let INTERCEPT_FETCH_REQUEST_JS_SOURCE = """
               init.method = result.method;
             }
             if (result.headers != null && Object.keys(result.headers).length > 0) {
-              init.headers = convertJsonToHeaders(result.headers);
+              init.headers = \(JAVASCRIPT_UTIL_VAR_NAME).convertJsonToHeaders(result.headers);
             }
-            if (result.body != null && result.body.length > 0)   {
-              init.body = convertArrayIntBodyToUint8Array(result.body);
+            if (\(JAVASCRIPT_UTIL_VAR_NAME).isString(result.body) || result.body == null) {
+              init.body = result.body;
+            } else if (result.body.length > 0) {
+              init.body = new Uint8Array(result.body);
             }
             if (result.mode != null && result.mode.length > 0) {
               init.mode = result.mode;
             }
             if (result.credentials != null) {
-              init.credentials = convertJsonToCredential(result.credentials);
+              init.credentials = \(JAVASCRIPT_UTIL_VAR_NAME).convertJsonToCredential(result.credentials);
             }
             if (result.cache != null && result.cache.length > 0) {
               init.cache = result.cache;
diff --git a/ios/Classes/PluginScriptsJS/JavaScriptBridgeJS.swift b/ios/Classes/PluginScriptsJS/JavaScriptBridgeJS.swift
index 2d4b7f89..9aa6334d 100644
--- a/ios/Classes/PluginScriptsJS/JavaScriptBridgeJS.swift
+++ b/ios/Classes/PluginScriptsJS/JavaScriptBridgeJS.swift
@@ -30,6 +30,213 @@ window.\(JAVASCRIPT_BRIDGE_NAME).callHandler = function() {
     });
 };
 \(WEB_MESSAGE_LISTENER_JS_SOURCE)
+\(UTIL_JS_SOURCE)
 """
 
 let PLATFORM_READY_JS_SOURCE = "window.dispatchEvent(new Event('flutterInAppWebViewPlatformReady'));";
+
+let JAVASCRIPT_UTIL_VAR_NAME = "window.\(JAVASCRIPT_BRIDGE_NAME)._Util"
+
+/*
+ https://github.com/github/fetch/blob/master/fetch.js
+ */
+let UTIL_JS_SOURCE = """
+\(JAVASCRIPT_UTIL_VAR_NAME) = {
+    support: {
+        searchParams: 'URLSearchParams' in window,
+        iterable: 'Symbol' in window && 'iterator' in Symbol,
+        blob:
+            'FileReader' in window &&
+            'Blob' in window &&
+            (function() {
+              try {
+                new Blob();
+                return true;
+              } catch (e) {
+                return false;
+              }
+            })(),
+        formData: 'FormData' in window,
+        arrayBuffer: 'ArrayBuffer' in window
+    },
+    isDataView: function(obj) {
+        return obj && DataView.prototype.isPrototypeOf(obj);
+    },
+    fileReaderReady: function(reader) {
+          return new Promise(function(resolve, reject) {
+                reader.onload = function() {
+                    resolve(reader.result);
+                };
+                reader.onerror = function() {
+                    reject(reader.error);
+                };
+          });
+    },
+    readBlobAsArrayBuffer: function(blob) {
+        var reader = new FileReader();
+        var promise = \(JAVASCRIPT_UTIL_VAR_NAME).fileReaderReady(reader);
+        reader.readAsArrayBuffer(blob);
+        return promise;
+    },
+    convertBodyToArrayBuffer: function(body) {
+        var viewClasses = [
+            '[object Int8Array]',
+            '[object Uint8Array]',
+            '[object Uint8ClampedArray]',
+            '[object Int16Array]',
+            '[object Uint16Array]',
+            '[object Int32Array]',
+            '[object Uint32Array]',
+            '[object Float32Array]',
+            '[object Float64Array]'
+        ];
+        var isArrayBufferView = null;
+        if (\(JAVASCRIPT_UTIL_VAR_NAME).support.arrayBuffer) {
+            isArrayBufferView =
+                ArrayBuffer.isView ||
+                function(obj) {
+                    return obj && viewClasses.indexOf(Object.prototype.toString.call(obj)) > -1;
+                };
+        }
+
+        var bodyUsed = false;
+
+        this._bodyInit = body;
+        if (!body) {
+            this._bodyText = '';
+        } else if (typeof body === 'string') {
+            this._bodyText = body;
+        } else if (\(JAVASCRIPT_UTIL_VAR_NAME).support.blob && Blob.prototype.isPrototypeOf(body)) {
+            this._bodyBlob = body;
+        } else if (\(JAVASCRIPT_UTIL_VAR_NAME).support.formData && FormData.prototype.isPrototypeOf(body)) {
+            this._bodyFormData = body;
+        } else if (\(JAVASCRIPT_UTIL_VAR_NAME).support.searchParams && URLSearchParams.prototype.isPrototypeOf(body)) {
+            this._bodyText = body.toString();
+        } else if (\(JAVASCRIPT_UTIL_VAR_NAME).support.arrayBuffer && \(JAVASCRIPT_UTIL_VAR_NAME).support.blob && \(JAVASCRIPT_UTIL_VAR_NAME).isDataView(body)) {
+            this._bodyArrayBuffer = bufferClone(body.buffer);
+            this._bodyInit = new Blob([this._bodyArrayBuffer]);
+        } else if (\(JAVASCRIPT_UTIL_VAR_NAME).support.arrayBuffer && (ArrayBuffer.prototype.isPrototypeOf(body) || isArrayBufferView(body))) {
+            this._bodyArrayBuffer = bufferClone(body);
+        } else {
+            this._bodyText = body = Object.prototype.toString.call(body);
+        }
+
+        this.blob = function () {
+            if (bodyUsed) {
+                return Promise.reject(new TypeError('Already read'));
+            }
+            bodyUsed = true;
+            if (this._bodyBlob) {
+                return Promise.resolve(this._bodyBlob);
+            } else if (this._bodyArrayBuffer) {
+                return Promise.resolve(new Blob([this._bodyArrayBuffer]));
+            } else if (this._bodyFormData) {
+                throw new Error('could not read FormData body as blob');
+            } else {
+                return Promise.resolve(new Blob([this._bodyText]));
+            }
+        };
+
+        if (this._bodyArrayBuffer) {
+            if (bodyUsed) {
+                return Promise.reject(new TypeError('Already read'));
+            }
+            bodyUsed = true;
+            if (ArrayBuffer.isView(this._bodyArrayBuffer)) {
+                return Promise.resolve(
+                  this._bodyArrayBuffer.buffer.slice(
+                    this._bodyArrayBuffer.byteOffset,
+                    this._bodyArrayBuffer.byteOffset + this._bodyArrayBuffer.byteLength
+                  )
+                );
+            } else {
+                return Promise.resolve(this._bodyArrayBuffer);
+            }
+        }
+        return this.blob().then(\(JAVASCRIPT_UTIL_VAR_NAME).readBlobAsArrayBuffer);
+    },
+    isString: function(variable) {
+        return typeof variable === 'string' || variable instanceof String;
+    },
+    convertBodyRequest: function(body) {
+        if (body == null) {
+            return new Promise((resolve, reject) => resolve(null));
+        }
+        if (\(JAVASCRIPT_UTIL_VAR_NAME).isString(body) || (\(JAVASCRIPT_UTIL_VAR_NAME).support.searchParams && body instanceof URLSearchParams)) {
+            return new Promise((resolve, reject) => resolve(body.toString()));
+        }
+        if (window.Response != null) {
+            return new Response(body).arrayBuffer().then(function(arrayBuffer) {
+                return Array.from(new Uint8Array(arrayBuffer));
+            });
+        }
+        return \(JAVASCRIPT_UTIL_VAR_NAME).convertBodyToArrayBuffer(body).then(function(arrayBuffer) {
+            return Array.from(new Uint8Array(arrayBuffer));
+        });
+    },
+    arrayBufferToString: function(arrayBuffer) {
+        return String.fromCharCode.apply(String, arrayBuffer);
+    },
+    isBodyFormData: function(bodyString) {
+        return bodyString.indexOf('------WebKitFormBoundary') >= 0;
+    },
+    getFormDataContentType: function(bodyString) {
+        var boundary = bodyString.substr(2, 40);
+        return 'multipart/form-data; boundary=' + boundary;
+    },
+    convertHeadersToJson: function(headers) {
+        var headersObj = {};
+        for (var header of headers.keys()) {
+          var value = headers.get(header);
+          headersObj[header] = value;
+        }
+        return headersObj;
+    },
+    convertJsonToHeaders: function(headersJson) {
+        return new Headers(headersJson);
+    },
+    convertCredentialsToJson: function(credentials) {
+        var credentialsObj = {};
+        if (window.FederatedCredential != null && credentials instanceof FederatedCredential) {
+          credentialsObj.type = credentials.type;
+          credentialsObj.id = credentials.id;
+          credentialsObj.name = credentials.name;
+          credentialsObj.protocol = credentials.protocol;
+          credentialsObj.provider = credentials.provider;
+          credentialsObj.iconURL = credentials.iconURL;
+        } else if (window.PasswordCredential != null && credentials instanceof PasswordCredential) {
+          credentialsObj.type = credentials.type;
+          credentialsObj.id = credentials.id;
+          credentialsObj.name = credentials.name;
+          credentialsObj.password = credentials.password;
+          credentialsObj.iconURL = credentials.iconURL;
+        } else {
+          credentialsObj.type = 'default';
+          credentialsObj.value = credentials;
+        }
+        return credentialsObj;
+    },
+    convertJsonToCredential: function(credentialsJson) {
+        var credentials;
+        if (window.FederatedCredential != null && credentialsJson.type === 'federated') {
+          credentials = new FederatedCredential({
+            id: credentialsJson.id,
+            name: credentialsJson.name,
+            protocol: credentialsJson.protocol,
+            provider: credentialsJson.provider,
+            iconURL: credentialsJson.iconURL
+          });
+        } else if (window.PasswordCredential != null && credentialsJson.type === 'password') {
+          credentials = new PasswordCredential({
+            id: credentialsJson.id,
+            name: credentialsJson.name,
+            password: credentialsJson.password,
+            iconURL: credentialsJson.iconURL
+          });
+        } else {
+          credentials = credentialsJson.value == null ? undefined : credentialsJson.value;
+        }
+        return credentials;
+    }
+};
+"""
diff --git a/lib/src/in_app_localhost_server.dart b/lib/src/in_app_localhost_server.dart
index 83188744..03593121 100755
--- a/lib/src/in_app_localhost_server.dart
+++ b/lib/src/in_app_localhost_server.dart
@@ -1,5 +1,6 @@
 import 'dart:io';
 import 'dart:async';
+import 'dart:typed_data';
 
 import 'package:flutter/services.dart' show rootBundle;
 
@@ -39,7 +40,8 @@ class InAppLocalhostServer {
         this._server = server;
 
         server.listen((HttpRequest request) async {
-          var body = [] as List<int>;
+          Uint8List body = Uint8List(0);
+
           var path = request.requestedUri.path;
           path = (path.startsWith('/')) ? path.substring(1) : path;
           path += (path.endsWith('/')) ? 'index.html' : '';
diff --git a/lib/src/types.dart b/lib/src/types.dart
index 2cd130a0..f35752ab 100755
--- a/lib/src/types.dart
+++ b/lib/src/types.dart
@@ -2873,7 +2873,7 @@ class AjaxRequestHeaders {
 ///Class that represents a JavaScript [XMLHttpRequest](https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest) object.
 class AjaxRequest {
   ///Data passed as a parameter to the `XMLHttpRequest.send()` method.
-  dynamic data;
+  dynamic? data;
 
   ///The HTTP request method of the `XMLHttpRequest` request.
   String? method;
@@ -3225,7 +3225,7 @@ class FetchRequest {
   Map<String, dynamic>? headers;
 
   ///Body of the request.
-  Uint8List? body;
+  dynamic? body;
 
   ///The mode used by the request.
   String? mode;
@@ -3291,9 +3291,7 @@ class FetchRequest {
         url: map["url"] != null ? Uri.parse(map["url"]) : null,
         method: map["method"],
         headers: map["headers"]?.cast<String, dynamic>(),
-        body: map["body"] != null
-            ? Uint8List.fromList(map["body"].cast<int>())
-            : null,
+        body: map["body"],
         mode: map["mode"],
         credentials: credentials,
         cache: map["cache"],
diff --git a/nodejs_server_test_auth_basic_and_ssl/index.js b/nodejs_server_test_auth_basic_and_ssl/index.js
index 87ac1ef7..f6bcdb16 100755
--- a/nodejs_server_test_auth_basic_and_ssl/index.js
+++ b/nodejs_server_test_auth_basic_and_ssl/index.js
@@ -9,6 +9,8 @@ const appHttps = express()
 const appAuthBasic = express()
 const fs = require('fs')
 const path = require('path')
+const bodyParser = require('body-parser');
+const multiparty = require('multiparty');
 
 var options = {
   key: fs.readFileSync('server-key.pem'),
@@ -117,14 +119,11 @@ appAuthBasic.get('/test-index', (req, res) => {
 appAuthBasic.listen(8081);
 
 
-
-// Parse URL-encoded bodies (as sent by HTML forms)
-app.use(express.urlencoded());
-
 app.use(cors());
 
+app.use(bodyParser.urlencoded({extended: false}));
 // Parse JSON bodies (as sent by API clients)
-app.use(express.json());
+app.use(bodyParser.json());
 
 app.use(express.static(__dirname + '/public'));
 
@@ -162,14 +161,27 @@ app.post("/test-post", (req, res) => {
 })
 
 app.post("/test-ajax-post", (req, res) => {
-  console.log(JSON.stringify(req.headers))
-  console.log(JSON.stringify(req.body))
-  res.set("Content-Type", "application/json")
-  res.send(JSON.stringify({
-    "firstname": req.body.firstname,
-    "lastname": req.body.lastname,
-  }))
-  res.end()
+  console.log(JSON.stringify(req.headers));
+  if (req.headers["content-type"].indexOf("multipart/form-data;") === 0) {
+    const form = new multiparty.Form();
+    form.parse(req, function(err, fields, files) {
+      console.log(fields);
+      res.set("Content-Type", "application/json")
+      res.send(JSON.stringify({
+        "firstname": fields.firstname[0],
+        "lastname": fields.lastname[0],
+      }));
+      res.end();
+    });
+  } else {
+    console.log(req.body);
+    res.set("Content-Type", "application/json")
+    res.send(JSON.stringify({
+      "firstname": req.body.firstname,
+      "lastname": req.body.lastname,
+    }));
+    res.end();
+  }
 })
 
 app.get("/test-download-file", (req, res) => {
@@ -184,4 +196,4 @@ app.get("/test-download-file", (req, res) => {
   res.end();
 })
 
-app.listen(8082)
\ No newline at end of file
+app.listen(8082)
diff --git a/nodejs_server_test_auth_basic_and_ssl/package-lock.json b/nodejs_server_test_auth_basic_and_ssl/package-lock.json
index 63329d22..04f0a5dc 100755
--- a/nodejs_server_test_auth_basic_and_ssl/package-lock.json
+++ b/nodejs_server_test_auth_basic_and_ssl/package-lock.json
@@ -252,6 +252,45 @@
       "resolved": "https://registry.npmjs.org/ms/-/ms-2.0.0.tgz",
       "integrity": "sha1-VgiurfwAvmwpAd9fmGF4jeDVl8g="
     },
+    "multiparty": {
+      "version": "4.2.2",
+      "resolved": "https://registry.npmjs.org/multiparty/-/multiparty-4.2.2.tgz",
+      "integrity": "sha512-NtZLjlvsjcoGrzojtwQwn/Tm90aWJ6XXtPppYF4WmOk/6ncdwMMKggFY2NlRRN9yiCEIVxpOfPWahVEG2HAG8Q==",
+      "requires": {
+        "http-errors": "~1.8.0",
+        "safe-buffer": "5.2.1",
+        "uid-safe": "2.1.5"
+      },
+      "dependencies": {
+        "http-errors": {
+          "version": "1.8.0",
+          "resolved": "https://registry.npmjs.org/http-errors/-/http-errors-1.8.0.tgz",
+          "integrity": "sha512-4I8r0C5JDhT5VkvI47QktDW75rNlGVsUf/8hzjCC/wkWI/jdTRmBb9aI7erSG82r1bjKY3F6k28WnsVxB1C73A==",
+          "requires": {
+            "depd": "~1.1.2",
+            "inherits": "2.0.4",
+            "setprototypeof": "1.2.0",
+            "statuses": ">= 1.5.0 < 2",
+            "toidentifier": "1.0.0"
+          }
+        },
+        "inherits": {
+          "version": "2.0.4",
+          "resolved": "https://registry.npmjs.org/inherits/-/inherits-2.0.4.tgz",
+          "integrity": "sha512-k/vGaX4/Yla3WzyMCvTQOXYeIHvqOKtnqBduzTHpzpQZzAskKMhZ2K+EnBiSM9zGSoIFeMpXKxa4dYeZIQqewQ=="
+        },
+        "safe-buffer": {
+          "version": "5.2.1",
+          "resolved": "https://registry.npmjs.org/safe-buffer/-/safe-buffer-5.2.1.tgz",
+          "integrity": "sha512-rp3So07KcdmmKbGvgaNxQSJr7bGVSVk5S9Eq1F+ppbRo70+YeaDxkw5Dd8NPN+GD6bjnYm2VuPuCXmpuYvmCXQ=="
+        },
+        "setprototypeof": {
+          "version": "1.2.0",
+          "resolved": "https://registry.npmjs.org/setprototypeof/-/setprototypeof-1.2.0.tgz",
+          "integrity": "sha512-E5LDX7Wrp85Kil5bhZv46j8jOeboKq5JMmYM3gVGdGH8xFpPWXUMsNrlODCrkoxMEeNi/XZIwuRvY4XNwYMJpw=="
+        }
+      }
+    },
     "negotiator": {
       "version": "0.6.2",
       "resolved": "https://registry.npmjs.org/negotiator/-/negotiator-0.6.2.tgz",
@@ -294,6 +333,11 @@
       "resolved": "https://registry.npmjs.org/qs/-/qs-6.7.0.tgz",
       "integrity": "sha512-VCdBRNFTX1fyE7Nb6FYoURo/SPe62QCaAyzJvUjwRaIsc+NePBEniHlvxFmmX56+HZphIGtV0XeCirBtpDrTyQ=="
     },
+    "random-bytes": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/random-bytes/-/random-bytes-1.0.0.tgz",
+      "integrity": "sha1-T2ih3Arli9P7lYSMMDJNt11kNgs="
+    },
     "range-parser": {
       "version": "1.2.1",
       "resolved": "https://registry.npmjs.org/range-parser/-/range-parser-1.2.1.tgz",
@@ -382,6 +426,14 @@
         "mime-types": "~2.1.24"
       }
     },
+    "uid-safe": {
+      "version": "2.1.5",
+      "resolved": "https://registry.npmjs.org/uid-safe/-/uid-safe-2.1.5.tgz",
+      "integrity": "sha512-KPHm4VL5dDXKz01UuEd88Df+KzynaohSL9fBh096KWAxSKZQDI2uBrVqtvRM4rwrIrRRKsdLNML/lnaaVSRioA==",
+      "requires": {
+        "random-bytes": "~1.0.0"
+      }
+    },
     "unpipe": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/unpipe/-/unpipe-1.0.0.tgz",
diff --git a/nodejs_server_test_auth_basic_and_ssl/package.json b/nodejs_server_test_auth_basic_and_ssl/package.json
index 049f42cf..6feac6cc 100755
--- a/nodejs_server_test_auth_basic_and_ssl/package.json
+++ b/nodejs_server_test_auth_basic_and_ssl/package.json
@@ -10,8 +10,10 @@
   "license": "ISC",
   "dependencies": {
     "basic-auth": "latest",
+    "body-parser": "^1.19.0",
     "cors": "^2.8.5",
     "express": "latest",
-    "https": "latest"
+    "https": "latest",
+    "multiparty": "^4.2.2"
   }
 }