Flutter WebviewPlugin remove header and footer of website - webview

Question

By implementation of FlutterWebviewPlugin, I want to show a particular website in a widget but without header and footer.
is this possible in Flutter?
I guess there is a function in FlutterWebviewPlugin class .evalJavascript('some code') but don't know how to use this function. can I add javascript code to this?
import 'package:flutter/material.dart';
import 'package:flutter_webview_plugin/flutter_webview_plugin.dart';
String url = "https://flutter.io/";
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Webview Example',
theme: ThemeData.dark(),
routes: {
"/": (_) => Home(),
"/webview": (_) => WebviewScaffold(
url: url,
withJavascript: true,
withLocalStorage: true,
withZoom: true,
)
},
);
}
}
class Home extends StatefulWidget {
#override
HomeState createState() => HomeState();
}
class HomeState extends State<Home> {
final webView = FlutterWebviewPlugin();
TextEditingController controller = TextEditingController(text: url);
#override
void initState() {
super.initState();
webView.close();
controller.addListener(() {
url = controller.text;
});
}
#override
void dispose() {
webView.dispose();
controller.dispose();
super.dispose();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("WebView"),
),
body: Center(
child: Column(
children: <Widget>[
Container(
padding: EdgeInsets.all(10.0),
child: TextField(
controller: controller,
),
),
RaisedButton(
child: Text("Open Webview"),
onPressed: () {
Navigator.of(context).pushNamed("/webview");
},
)
],
),
)
);
}
}

Answer 1

I suggest using Flutter's official WebView plugin: webview_flutter
The plugin also has a method that can run Javascript using WebViewController.evaluateJavascript(String). This method is recommended to be run after WebView.onPageFinished callback.
Your WebView widget should look like this.
WebView(
initialUrl: 'https://flutter.dev',
javascriptMode: JavascriptMode.unrestricted,
onWebViewCreated: (WebViewController webViewController) {
_webViewController = webViewController;
_controller.complete(webViewController);
},
onProgress: (int progress) {
print("WebView is loading (progress : $progress%)");
},
onPageStarted: (String url) {
print('Page started loading: $url');
},
onPageFinished: (String url) {
print('Page finished loading: $url');
// Removes header and footer from page
_webViewController
.evaluateJavascript("javascript:(function() { " +
"var head = document.getElementsByTagName('header')[0];" +
"head.parentNode.removeChild(head);" +
"var footer = document.getElementsByTagName('footer')[0];" +
"footer.parentNode.removeChild(footer);" +
"})()")
.then((value) => debugPrint('Page finished loading Javascript'))
.catchError((onError) => debugPrint('$onError'));
},
);
Here's a complete sample that you can try.
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:webview_flutter/webview_flutter.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
final Completer<WebViewController> _controller =
Completer<WebViewController>();
WebViewController _webViewController;
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Builder(builder: (BuildContext context) {
return WebView(
initialUrl: 'https://flutter.dev',
javascriptMode: JavascriptMode.unrestricted,
onWebViewCreated: (WebViewController webViewController) {
_webViewController = webViewController;
_controller.complete(webViewController);
},
onProgress: (int progress) {
print("WebView is loading (progress : $progress%)");
},
javascriptChannels: <JavascriptChannel>{
_toasterJavascriptChannel(context),
},
navigationDelegate: (NavigationRequest request) {
if (request.url.startsWith('https://www.youtube.com/')) {
print('blocking navigation to $request}');
return NavigationDecision.prevent;
}
print('allowing navigation to $request');
return NavigationDecision.navigate;
},
onPageStarted: (String url) {
print('Page started loading: $url');
},
onPageFinished: (String url) {
print('Page finished loading: $url');
_webViewController
.evaluateJavascript("javascript:(function() { " +
"var head = document.getElementsByTagName('header')[0];" +
"head.parentNode.removeChild(head);" +
"var footer = document.getElementsByTagName('footer')[0];" +
"footer.parentNode.removeChild(footer);" +
"})()")
.then((value) => debugPrint('Page finished loading Javascript'))
.catchError((onError) => debugPrint('$onError'));
},
gestureNavigationEnabled: true,
);
}),
);
}
JavascriptChannel _toasterJavascriptChannel(BuildContext context) {
return JavascriptChannel(
name: 'Toaster',
onMessageReceived: (JavascriptMessage message) {
// ignore: deprecated_member_use
Scaffold.of(context).showSnackBar(
SnackBar(content: Text(message.message)),
);
});
}
}
How the app looks running

Answer 2

_webViewController.runJavascript(
"document.getElementsByTagName('header')[0].style.display='none'");
_webViewController.runJavascript(
"document.getElementsByTagName('footer')[0].style.display='none'");

Answer 3

You can use the flutter_inappwebview plugin (I'm the author) and inject an UserScript at UserScriptInjectionTime.AT_DOCUMENT_START to hide or remove HTML elements when the web page loads (check JavaScript - User Scripts official docs for User Scripts details).
As I have already answered here for a similar issue, here is a code example using the current latest version 6 (6.0.0-beta.18) with URL https://getmobie.de/impressum that removes the header and footer HTML elements:
import 'dart:collection';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter_inappwebview/flutter_inappwebview.dart';
Future main() async {
WidgetsFlutterBinding.ensureInitialized();
if (!kIsWeb &&
kDebugMode &&
defaultTargetPlatform == TargetPlatform.android) {
await InAppWebViewController.setWebContentsDebuggingEnabled(kDebugMode);
}
runApp(const MaterialApp(home: MyApp()));
}
class MyApp extends StatefulWidget {
const MyApp({Key? key}) : super(key: key);
#override
State<MyApp> createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
final GlobalKey webViewKey = GlobalKey();
InAppWebViewController? webViewController;
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text("InAppWebView test"),
),
body: Column(children: <Widget>[
Expanded(
child: InAppWebView(
key: webViewKey,
initialUrlRequest:
URLRequest(url: WebUri("https://getmobie.de/impressum")),
initialUserScripts: UnmodifiableListView([
UserScript(source: """
window.addEventListener('DOMContentLoaded', function(event) {
var header = document.querySelector('.elementor-location-header'); // use here the correct CSS selector for your use case
if (header != null) {
header.remove(); // remove the HTML element. Instead, to simply hide the HTML element, use header.style.display = 'none';
}
var footer = document.querySelector('.elementor-location-footer'); // use here the correct CSS selector for your use case
if (footer != null) {
footer.remove(); // remove the HTML element. Instead, to simply hide the HTML element, use footer.style.display = 'none';
}
});
""", injectionTime: UserScriptInjectionTime.AT_DOCUMENT_START)
]),
onWebViewCreated: (controller) {
webViewController = controller;
},
),
),
]));
}
}
For your use case, use the right CSS selector inside the user script js source to correctly get and remove the header and footer HTML elements from your web page!