How to enable and disable Javascript in Flutter WebView

If you are new to flutter webview and you are looking for a simple code example on how to create a simple webview in flutter I will suggest you visit this page how to create flutter webview

This code example will explore how to enable and disable javascript in flutter webview when a button is clicked.

Enabling javascript in a webview can cause security issues but without javascript enable, the flutter webview will not properly display content of web pages that depend on javascript.

You can copy and adopt this source code example to your flutter project without reinventing the wheel.

1. Add flutter_webview plugin in pubspec.yaml

name: flutter_app
description: A new Flutter application.

# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# Read more about versioning at semver.org.
version: 1.0.0+1

environment:
  sdk: ">=2.0.0-dev.68.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter

  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  cupertino_icons: ^0.1.2
  http: 0.12.0
  ##sqflite: 0.13.0+1
  path_provider: 0.4.1
  ##zoomable_image: 1.2.1+1
  ##multi_image_picker: 2.3.32
  dio: 2.0.22
  shared_preferences: 0.4.3
  flare_flutter: any
  flutter_webview_plugin: 0.3.0+2
  webview_flutter: 0.2.0


dev_dependencies:
  flutter_test:
    sdk: flutter


# For information on the generic Dart part of this file, see the
# following page: https://www.dartlang.org/tools/pub/pubspec

# The following section is specific to Flutter.
flutter:

  # The following line ensures that the Material Icons font is
  # included with your application, so that you can use the icons in
  # the material Icons class.
  uses-material-design: true

  assets:
    - assets/html_code.html
    - assets/iframe.html
    - assets/js_lib.html


  # To add assets to your application, add an assets section, like this:
  # assets:
  #  - images/a_dot_burr.jpeg
  #  - images/a_dot_ham.jpeg

  # An image asset can refer to one or more resolution-specific "variants", see
  # https://flutter.io/assets-and-images/#resolution-aware.

  # For details regarding adding assets from package dependencies, see
  # https://flutter.io/assets-and-images/#from-packages

  # To add custom fonts to your application, add a fonts section here,
  # in this "flutter" section. Each entry in this list should have a
  # "family" key with the font family name, and a "fonts" key with a
  # list giving the asset and other descriptors for the font. For
  # example:
  # For details regarding fonts from package dependencies,
  # see https://flutter.io/custom-fonts/#from-packages

2. Create main.dart if it does not already exist

This is the entry point of our application. Open the file and add the code below.

import 'package:flutter/material.dart';
import 'enable_javascript_task-2.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: EnableJavacriptWebView(),
    );
  }
}

In the above code, we have theĀ enable_javascript_task-2.dartĀ file. This file is where we will add our simple flutter webview widget class

3. Create enable_javascript_task_2.dart in the lib folder

Create a new dart file in the lib folder. I have named it enable_javascript_task-2.dartbut feel free to choose a name of your choice

Open the file and add the code below.

import 'package:flutter/material.dart';
import 'package:flutter_webview_plugin/flutter_webview_plugin.dart';
import 'package:webview_flutter/webview_flutter.dart';

class EnableJavacriptWebView extends StatefulWidget {
  @override
  EnableJavacriptWebViewState createState() {
    return new EnableJavacriptWebViewState();
  }
}

class EnableJavacriptWebViewState extends State<EnableJavacriptWebView> {
  bool _isJSEnabled = false;

  _onChanged() {
    setState(() {
      _isJSEnabled = !_isJSEnabled;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text("Enable / Disable JS in WEbview")),
      body: Stack(
        children: [
          WebView(
            initialUrl: 'https://inducesmile.com',
            javascriptMode: _isJSEnabled
                ? JavascriptMode.unrestricted
                : JavascriptMode.disabled,
          ),
          Positioned(
            bottom: 15.0,
            child: Align(
              alignment: Alignment.center,
              child: RaisedButton(
                child: Text(_isJSEnabled ? "Disable JS" : "Enable JS"),
                color: Colors.red,
                onPressed: _onChanged,
              ),
            ),
          ),
        ],
      ),
    );
  }
}

As you can see above, we have imported flutter webview and assign the web url we want to access to flutter webview url property

4. Run your app

You can use flutter command to run your app – $ flutter run

If everything goes well, you will see a website similar to the image below in your flutter webview.

If you have any question or suggestions kindly use the comment box or you can contact us directly through our contact page below.

 

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