Js code contains timer, exit webvie_scaffold, and the timer still runs.

I use the webview_scaffold to open a web.
the webpage contains contains a timer.
this is a html file I have used:
```

Timer

var s;

function $(id){

return document.getElementById(id);

}

function display(){

var date = new Date();

var str = date.getTime();

$("content").value = str;

console.log("this this a console log..." + str);

s = setTimeout('display()',1000);

}

window.onload = function(){

$("start").onclick =function(){display();}

$("stop").onclick = function(){clearTimeout(s);}

}

```
It means that change the display num and print some log per second.

this is my webviewPage.dart
```
//! WebViewPage
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_webview_plugin/flutter_webview_plugin.dart';

class AppWebView extends StatelessWidget {
final String url;
final String title;

AppWebView(this.url, this.title);

_renderTitle() {
if (url == null || url.length == 0) {
return new Text(title);
}
return new Row(children: [
//new Expanded(child: new Container()),
new Text(title)
]);
}

@override
Widget build(BuildContext context) {
return new WebviewScaffold(
withJavascript: true,
hidden: false,
url: url,
scrollBar:false,
withLocalUrl: true,
appBar: new AppBar(
title: _renderTitle(),
),
);
}
}
```
when I open the webview to the html file,then I press the start button on this web.Finally I exit the webview.

this is my log:
```
I/flutter ( 4095): 运维页面
I/zygote64( 4095): Compiler allocated 8MB to compile void android.view.ViewRootImpl.performTraversals()
D/ViewRootImpl@d8ee1fe[MainActivity]( 4095): ViewPostIme pointer 0
D/ViewRootImpl@d8ee1fe[MainActivity]( 4095): ViewPostIme pointer 1
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273611702", source: http://192.168.10.104/test.html (24)
V/InputMethodManager( 4095): Starting input: tba=android.view.inputmethod.EditorInfo@560ef34 nm : com.example.dfelectricapp ic=null
I/InputMethodManager( 4095): startInputInner - mService.startInputOrWindowGainedFocus
D/InputMethodManager( 4095): HSIFW - flag : 0 Pid : 4095
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273612709", source: http://192.168.10.104/test.html (24)
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273613719", source: http://192.168.10.104/test.html (24)
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273614726", source: http://192.168.10.104/test.html (24)
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273615730", source: http://192.168.10.104/test.html (24)
D/ViewRootImpl@d8ee1fe[MainActivity]( 4095): ViewPostIme pointer 0
D/ViewRootImpl@d8ee1fe[MainActivity]( 4095): ViewPostIme pointer 1
I/flutter ( 4095): 运维页面show web
I/flutter ( 4095): this is webview dispose
D/InputMethodManager( 4095): HSIFW - flag : 0 Pid : 4095
V/InputMethodManager( 4095): Starting input: tba=android.view.inputmethod.EditorInfo@95fe15d nm : com.example.dfelectricapp ic=null
I/InputMethodManager( 4095): startInputInner - mService.startInputOrWindowGainedFocus
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273617383", source: http://192.168.10.104/test.html (24)
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273619384", source: http://192.168.10.104/test.html (24)
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273621385", source: http://192.168.10.104/test.html (24)
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273623384", source: http://192.168.10.104/test.html (24)
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273625384", source: http://192.168.10.104/test.html (24)
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273627383", source: http://192.168.10.104/test.html (24)
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273629384", source: http://192.168.10.104/test.html (24)
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273631384", source: http://192.168.10.104/test.html (24)
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273633385", source: http://192.168.10.104/test.html (24)
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273635384", source: http://192.168.10.104/test.html (24)
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273637385", source: http://192.168.10.104/test.html (24)
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273639385", source: http://192.168.10.104/test.html (24)
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273641385", source: http://192.168.10.104/test.html (24)
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273643385", source: http://192.168.10.104/test.html (24)
I/chromium( 4095): [INFO:CONSOLE(24)] "this this a console log...1545273645385", source: http://192.168.10.104/test.html (24)

```
You can see that I've quit the webview but the log is still being printed.

I try to solve this problem.So here's what I did.
In the webview_scaffold.dart
```
@override
void dispose() {
super.dispose();
webviewReference.reloadUrl(""); //! I add this line
_resizeTimer?.cancel();
webviewReference.close();
if (widget.hidden) {
_onStateChanged.cancel();
}
print("this is webview dispose");
webviewReference.dispose();
}
```
It worked,But I don't know the reason.
Am I right?
I want to know why the js consle log still being printed.
Thanks very much.

btw:
this is flutter doctor print:
Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel beta, v0.11.7, on Microsoft Windows [Version 10.0.17134.471], locale zh-CN)
[√] Android toolchain - develop for Android devices (Android SDK 28.0.3)
[√] Android Studio (version 3.2)
[√] Connected device (1 available)

• No issues found!

this is the dependencies:
flutter_webview_plugin: ^0.3.0+2