diff --git a/CHANGELOG.md b/CHANGELOG.md
index ffefa3a5..eb6d6973 100755
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 5.1.0+3
+
+- Fixed "Unsupported operation: Platform._operatingSystem" when compiling for Web again [#507](https://github.com/pichillilorenzo/flutter_inappwebview/issues/507)
+
 ## 5.1.0+2
 
 - Fixed missing MATCH_PARENT layout params to the WebView on Android when it is wrapped by PullToRefreshLayout
diff --git a/example/.flutter-plugins-dependencies b/example/.flutter-plugins-dependencies
index 1933c739..d5d52e2c 100644
--- a/example/.flutter-plugins-dependencies
+++ b/example/.flutter-plugins-dependencies
@@ -1 +1 @@
-{"info":"This is a generated file; do not edit or check into version control.","plugins":{"ios":[{"name":"flutter_downloader","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_downloader-1.5.2/","dependencies":[]},{"name":"flutter_inappwebview","path":"/Users/lorenzopichilli/Desktop/flutter_inappwebview/","dependencies":[]},{"name":"integration_test","path":"/Users/lorenzopichilli/flutter/packages/integration_test/","dependencies":[]},{"name":"path_provider","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider-2.0.0-nullsafety/","dependencies":[]},{"name":"permission_handler","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/permission_handler-5.1.0+2/","dependencies":[]},{"name":"url_launcher","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher-6.0.0-nullsafety.6/","dependencies":[]}],"android":[{"name":"flutter_downloader","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_downloader-1.5.2/","dependencies":[]},{"name":"flutter_inappwebview","path":"/Users/lorenzopichilli/Desktop/flutter_inappwebview/","dependencies":[]},{"name":"integration_test","path":"/Users/lorenzopichilli/flutter/packages/integration_test/","dependencies":[]},{"name":"path_provider","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider-2.0.0-nullsafety/","dependencies":[]},{"name":"permission_handler","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/permission_handler-5.1.0+2/","dependencies":[]},{"name":"url_launcher","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher-6.0.0-nullsafety.6/","dependencies":[]}],"macos":[{"name":"path_provider_macos","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider_macos-0.0.5-nullsafety/","dependencies":[]},{"name":"url_launcher_macos","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher_macos-0.1.0-nullsafety.2/","dependencies":[]}],"linux":[{"name":"path_provider_linux","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider_linux-0.2.0-nullsafety/","dependencies":[]},{"name":"url_launcher_linux","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher_linux-0.1.0-nullsafety.3/","dependencies":[]}],"windows":[{"name":"path_provider_windows","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider_windows-0.1.0-nullsafety.3/","dependencies":[]},{"name":"url_launcher_windows","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher_windows-0.1.0-nullsafety.2/","dependencies":[]}],"web":[]},"dependencyGraph":[{"name":"flutter_downloader","dependencies":[]},{"name":"flutter_inappwebview","dependencies":[]},{"name":"integration_test","dependencies":[]},{"name":"path_provider","dependencies":["path_provider_macos","path_provider_linux","path_provider_windows"]},{"name":"path_provider_linux","dependencies":[]},{"name":"path_provider_macos","dependencies":[]},{"name":"path_provider_windows","dependencies":[]},{"name":"permission_handler","dependencies":[]},{"name":"url_launcher","dependencies":["url_launcher_linux","url_launcher_macos","url_launcher_windows"]},{"name":"url_launcher_linux","dependencies":[]},{"name":"url_launcher_macos","dependencies":[]},{"name":"url_launcher_windows","dependencies":[]}],"date_created":"2021-03-06 16:03:42.653087","version":"2.1.0-10.0.pre"}
\ No newline at end of file
+{"info":"This is a generated file; do not edit or check into version control.","plugins":{"ios":[{"name":"flutter_downloader","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_downloader-1.5.2/","dependencies":[]},{"name":"flutter_inappwebview","path":"/Users/lorenzopichilli/Desktop/flutter_inappwebview/","dependencies":[]},{"name":"integration_test","path":"/Users/lorenzopichilli/flutter/packages/integration_test/","dependencies":[]},{"name":"path_provider","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider-2.0.0-nullsafety/","dependencies":[]},{"name":"permission_handler","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/permission_handler-5.1.0+2/","dependencies":[]},{"name":"url_launcher","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher-6.0.0-nullsafety.6/","dependencies":[]}],"android":[{"name":"flutter_downloader","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_downloader-1.5.2/","dependencies":[]},{"name":"flutter_inappwebview","path":"/Users/lorenzopichilli/Desktop/flutter_inappwebview/","dependencies":[]},{"name":"integration_test","path":"/Users/lorenzopichilli/flutter/packages/integration_test/","dependencies":[]},{"name":"path_provider","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider-2.0.0-nullsafety/","dependencies":[]},{"name":"permission_handler","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/permission_handler-5.1.0+2/","dependencies":[]},{"name":"url_launcher","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher-6.0.0-nullsafety.6/","dependencies":[]}],"macos":[{"name":"path_provider_macos","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider_macos-0.0.5-nullsafety/","dependencies":[]},{"name":"url_launcher_macos","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher_macos-0.1.0-nullsafety.2/","dependencies":[]}],"linux":[{"name":"path_provider_linux","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider_linux-0.2.0-nullsafety/","dependencies":[]},{"name":"url_launcher_linux","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher_linux-0.1.0-nullsafety.3/","dependencies":[]}],"windows":[{"name":"path_provider_windows","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider_windows-0.1.0-nullsafety.3/","dependencies":[]},{"name":"url_launcher_windows","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher_windows-0.1.0-nullsafety.2/","dependencies":[]}],"web":[]},"dependencyGraph":[{"name":"flutter_downloader","dependencies":[]},{"name":"flutter_inappwebview","dependencies":[]},{"name":"integration_test","dependencies":[]},{"name":"path_provider","dependencies":["path_provider_macos","path_provider_linux","path_provider_windows"]},{"name":"path_provider_linux","dependencies":[]},{"name":"path_provider_macos","dependencies":[]},{"name":"path_provider_windows","dependencies":[]},{"name":"permission_handler","dependencies":[]},{"name":"url_launcher","dependencies":["url_launcher_linux","url_launcher_macos","url_launcher_windows"]},{"name":"url_launcher_linux","dependencies":[]},{"name":"url_launcher_macos","dependencies":[]},{"name":"url_launcher_windows","dependencies":[]}],"date_created":"2021-03-08 10:08:44.020151","version":"2.1.0-10.0.pre"}
\ No newline at end of file
diff --git a/lib/src/cookie_manager.dart b/lib/src/cookie_manager.dart
index 0b46ce77..7839a501 100755
--- a/lib/src/cookie_manager.dart
+++ b/lib/src/cookie_manager.dart
@@ -1,6 +1,7 @@
 import 'dart:async';
 import 'dart:io';
 
+import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 
 import 'in_app_webview/in_app_webview_controller.dart';
@@ -70,7 +71,7 @@ class CookieManager {
     assert(domain.isNotEmpty);
     assert(path.isNotEmpty);
 
-    if (Platform.isIOS) {
+    if (defaultTargetPlatform == TargetPlatform.iOS) {
       var platformUtil = PlatformUtil();
       var version = double.tryParse(await platformUtil.getSystemVersion());
       if (version != null && version < 11.0) {
@@ -166,7 +167,7 @@ class CookieManager {
       InAppWebViewController? iosBelow11WebViewController}) async {
     assert(url.toString().isNotEmpty);
 
-    if (Platform.isIOS) {
+    if (defaultTargetPlatform == TargetPlatform.iOS) {
       var platformUtil = PlatformUtil();
       var version = double.tryParse(await platformUtil.getSystemVersion());
       if (version != null && version < 11.0) {
@@ -265,7 +266,7 @@ class CookieManager {
     assert(url.toString().isNotEmpty);
     assert(name.isNotEmpty);
 
-    if (Platform.isIOS) {
+    if (defaultTargetPlatform == TargetPlatform.iOS) {
       var platformUtil = PlatformUtil();
       var version = double.tryParse(await platformUtil.getSystemVersion());
       if (version != null && version < 11.0) {
@@ -321,7 +322,7 @@ class CookieManager {
     assert(url.toString().isNotEmpty);
     assert(name.isNotEmpty);
 
-    if (Platform.isIOS) {
+    if (defaultTargetPlatform == TargetPlatform.iOS) {
       var platformUtil = PlatformUtil();
       var version = double.tryParse(await platformUtil.getSystemVersion());
       if (version != null && version < 11.0) {
@@ -365,7 +366,7 @@ class CookieManager {
 
     assert(url.toString().isNotEmpty);
 
-    if (Platform.isIOS) {
+    if (defaultTargetPlatform == TargetPlatform.iOS) {
       var platformUtil = PlatformUtil();
       var version = double.tryParse(await platformUtil.getSystemVersion());
       if (version != null && version < 11.0) {
diff --git a/lib/src/in_app_webview/in_app_webview_controller.dart b/lib/src/in_app_webview/in_app_webview_controller.dart
index bd116b8f..655426cd 100644
--- a/lib/src/in_app_webview/in_app_webview_controller.dart
+++ b/lib/src/in_app_webview/in_app_webview_controller.dart
@@ -1908,7 +1908,7 @@ class InAppWebViewController {
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkusercontentcontroller/1537448-adduserscript
   Future<void> addUserScript({required UserScript userScript}) async {
-    assert(_webview?.windowId == null || !Platform.isIOS);
+    assert(_webview?.windowId == null || defaultTargetPlatform != TargetPlatform.iOS);
 
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('userScript', () => userScript.toMap());
@@ -1924,7 +1924,7 @@ class InAppWebViewController {
   ///There isn't any way to add/remove user scripts specific to iOS window WebViews.
   ///This is a limitation of the native iOS WebKit APIs.
   Future<void> addUserScripts({required List<UserScript> userScripts}) async {
-    assert(_webview?.windowId == null || !Platform.isIOS);
+    assert(_webview?.windowId == null || defaultTargetPlatform != TargetPlatform.iOS);
 
     for (var i = 0; i < userScripts.length; i++) {
       await addUserScript(userScript: userScripts[i]);
@@ -1939,7 +1939,7 @@ class InAppWebViewController {
   ///There isn't any way to add/remove user scripts specific to iOS window WebViews.
   ///This is a limitation of the native iOS WebKit APIs.
   Future<bool> removeUserScript({required UserScript userScript}) async {
-    assert(_webview?.windowId == null || !Platform.isIOS);
+    assert(_webview?.windowId == null || defaultTargetPlatform != TargetPlatform.iOS);
 
     var index = _userScripts.indexOf(userScript);
     if (index == -1) {
@@ -1962,7 +1962,7 @@ class InAppWebViewController {
   ///There isn't any way to add/remove user scripts specific to iOS window WebViews.
   ///This is a limitation of the native iOS WebKit APIs.
   Future<void> removeUserScriptsByGroupName({required String groupName}) async {
-    assert(_webview?.windowId == null || !Platform.isIOS);
+    assert(_webview?.windowId == null || defaultTargetPlatform != TargetPlatform.iOS);
 
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('groupName', () => groupName);
@@ -1977,7 +1977,7 @@ class InAppWebViewController {
   ///This is a limitation of the native iOS WebKit APIs.
   Future<void> removeUserScripts(
       {required List<UserScript> userScripts}) async {
-    assert(_webview?.windowId == null || !Platform.isIOS);
+    assert(_webview?.windowId == null || defaultTargetPlatform != TargetPlatform.iOS);
 
     for (var i = 0; i < userScripts.length; i++) {
       await removeUserScript(userScript: userScripts[i]);
@@ -1992,7 +1992,7 @@ class InAppWebViewController {
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkusercontentcontroller/1536540-removealluserscripts
   Future<void> removeAllUserScripts() async {
-    assert(_webview?.windowId == null || !Platform.isIOS);
+    assert(_webview?.windowId == null || defaultTargetPlatform != TargetPlatform.iOS);
 
     _userScripts.clear();
     Map<String, dynamic> args = <String, dynamic>{};
@@ -2059,9 +2059,9 @@ class InAppWebViewController {
   Future<String?> saveWebArchive(
       {required String filePath, bool autoname = false}) async {
     if (!autoname) {
-      if (Platform.isAndroid) {
+      if (defaultTargetPlatform == TargetPlatform.android) {
         assert(filePath.endsWith("." + WebArchiveFormat.MHT.toValue()));
-      } else if (Platform.isIOS) {
+      } else if (defaultTargetPlatform == TargetPlatform.iOS) {
         assert(filePath.endsWith("." + WebArchiveFormat.WEBARCHIVE.toValue()));
       }
     }
diff --git a/pubspec.yaml b/pubspec.yaml
index 8b10c907..b2d9db56 100755
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: flutter_inappwebview
 description: A Flutter plugin that allows you to add an inline webview, to use an headless webview, and to open an in-app browser window.
-version: 5.1.0+2
+version: 5.1.0+3
 homepage: https://github.com/pichillilorenzo/flutter_inappwebview
 
 environment: