Xamarin form webview Eval not calling javascript

Question

I use following code to load page to MyWebView:

private void DisplayLocalPage(string filename)
{
    var html = new HtmlWebViewSource();
    html.BaseUrl = DependencyService.Get<IBaseUrl>().Get();
    html.Html = ReadFile(filename);
    MyWebView.Source = html;
    MyWebView.Eval("alert(200)");
}

Page is rendered well - all scripts run too, but this alert isn't fired, what are possible reasons?

You should allow the permission to run scripts. Does it work if you write it in the document ready event of JS of the loaded page? — Rohit Vipin Mathews
– Rohit Vipin Mathews, Commented Aug 3, 2016 at 10:38
wait, according to this: developer.xamarin.com/recipes/cross-platform/xamarin-forms/… there is no need to create custom renderers and so on, why then? — prompteus
– prompteus, Commented Aug 3, 2016 at 10:52
Its only required if you need some advanced options, also there is an ExtendedWebView by XLabs. Apart from that with this piece of code its hard to explain further. — Rohit Vipin Mathews
– Rohit Vipin Mathews, Commented Aug 3, 2016 at 10:58

Kamil Smrčka · Accepted Answer · 2017-01-03 16:51:29Z

3

Please try this:

webView.Navigated += (o, s) => {
     webView.Eval("alert('text')");
     };

edited Jan 3, 2017 at 16:51

answered Jan 3, 2017 at 16:22

Kamil Smrčka

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4 Comments

happymacarts Over a year ago

an explanation of your solution is usually helpful

prompteus Over a year ago

@happymacarts the explanation is in my answer.

John Lay Over a year ago

Both @Kamil Smrčka and cuddlecheek are correct. The reason the JavaScript isn't firing is because the page hasn't finished loading. The description from the documentation (developer.xamarin.com/api/event/Xamarin.Forms.WebView.Navigated) for the Navigated event is: "Event that is raised after navigation completes." So in the above answer Kamil is subscribing to the Navigated event (in this case the page load complete event) and executing his JavaScript after it fires.

LOST Over a year ago

@JohnLay That still does not work for me. No alert is displayed.

prompteus · Accepted Answer · 2016-08-05 22:35:54Z

0

I think I figured out why it might not work. The Eval is triggered before the WebView is fully initialized or web page is rendered, so the script is trigerred, but doesn't have any effect.

answered Aug 5, 2016 at 22:35

prompteus

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