How to Inject JavaScript in The Wp7 Webbrowser Control

How to inject Javascript in the WP7 WebBrowser control?

Unfortunately WebBrowser.Document is not available on WP7. But you can create and call a JavaScript function using InvokeScript. Have a look over here where I describe how.

In short: you don't use .Document and C# but create a piece of JavaScript instead. You then call eval with this script as parameter to invoke it. Like this:

webBrowser1.InvokeScript("eval", "  ...code goes here... ");

Can I inject JavaScript object into WebBrowser?

I just encountered this myself.

The problem is that you are not sending in the parameter as a string.
eval takes a string as parameter and if you invoke this script with your current parameter it will translate into:

eval(function Player() {  this.play = function(e) { window.external.notify(e); }})

when what you really want to do is:

eval("function Player() {  this.play = function(e) { window.external.notify(e); }}")

So the correct this, try:

webbrowser.InvokeScript("eval", "\"function Player() {  this.play = function(e) { window.external.notify(e); }}\"");

Inject/serve custom CSS in WP8 WebBrowser Control

Yes. By invoking WebBrowser.InvokeScript after WebBrowser.LoadCompleted you can execute arbitrary javascript code in a webbrowser control. Web apps can then use WebBrowser.ScriptNotify to talk back to C#.

See more @ How to inject Javascript in the WP7 WebBrowser control?

How to inject CSS in WebBrowser control?

I didn't try this myself but since CSS style rules can be included in a document using the <style> tag as in:

<html>
<head>
<style type="text/css">
    h1 {color:red}
    p {color:blue}
</style>
</head>

you could try giving:

HtmlElement head = webBrowser1.Document.GetElementsByTagName("head")[0];
HtmlElement styleEl = webBrowser1.Document.CreateElement("style");
IHTMLStyleElement element = (IHTMLStyleElement)styleEl.DomElement;
IHTMLStyleSheetElement styleSheet = element.styleSheet;
styleSheet.cssText = @"h1 { color: red }";
head.AppendChild(styleEl);

a go. You can find more info on the IHTMLStyleElement here.

Edit

It seems the answer is much much simpler than I originally thought:

  using mshtml;

  IHTMLDocument2 doc = (webBrowser1.Document.DomDocument) as IHTMLDocument2;
  // The first parameter is the url, the second is the index of the added style sheet.
  IHTMLStyleSheet ss = doc.createStyleSheet("", 0);

  // Now that you have the style sheet you have a few options:
  // 1. You can just set the content as text.
  ss.cssText = @"h1 { color: blue; }";
  // 2. You can add/remove style rules.
  int index = ss.addRule("h1", "color: red;");
  ss.removeRule(index);
  // You can even walk over the rules using "ss.rules" and modify them.

I wrote a small test project to verify that this works. I arrived at this final result by doing a search on MSDN for IHTMLStyleSheet, upon which I happened across this page, this page and this one.

How does CefSharp inject JS into new pages opened in Windows.open

The window.open call will create a new popup. You can get load events for popups (and main browser) by implementing LoadHandler.

A basic example would look something like:

public class CustomLoadHandler : CefSharp.Handler.LoadHandler
{
    protected override void OnFrameLoadStart(IWebBrowser chromiumWebBrowser, FrameLoadStartEventArgs args)
    {
        // Execute script before DOM has started loading
        // window.open will create a new popup, check IsPopup = true
        // Add any additional checks like comparing the URL that meet your requirements 
        // Execute your script here on in OnFrameLoadEnd. Not both
        if (args.Browser.IsPopup && args.Frame.Url.EndsWith("page2.html"))
        {
            string script = System.IO.File.ReadAllText(@"c:\my.js");
            args.Frame.ExecuteJavaScriptAsync(script);
        }
        base.OnFrameLoadStart(chromiumWebBrowser, args);
    }

    protected override void OnFrameLoadEnd(IWebBrowser chromiumWebBrowser, FrameLoadEndEventArgs args)
    {
        // Execute script before DOM has started loading
        // window.open will create a new popup, check IsPopup = true
        // Add any additional checks like comparing the URL that meet your requirements
        // Execute your script here on in OnFrameLoadStart. Not both
        if (args.Browser.IsPopup && args.Frame.Url.EndsWith("page2.html"))
        {
            string script = System.IO.File.ReadAllText(@"c:\my.js");
            args.Frame.ExecuteJavaScriptAsync(script);
        }

        base.OnFrameLoadEnd(chromiumWebBrowser, args);
    }
}

chromiumWebBrowser.LoadHandler = new CustomLoadHandler();

How to Inject JavaScript in The Wp7 Webbrowser Control