Inject JavaScript with jQuery at runtime into WebBrowser

I have desktop application with WebBrowser control and try to inject JavaScript into loaded page.

For this I added two script elements:

private static void AddJQueryElement(HtmlElement head)
{
    HtmlElement scriptEl = head.Document.CreateElement("script");
    IHTMLScriptElement jQueryElement = (IHTMLScriptElement)scriptEl.DomElement;
    jQueryElement.src = @"http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js";

    head.AppendChild(scriptEl);           
}

private static void AddScriptElement(HtmlElement head)
{
    HtmlElement scriptEl = head.Document.CreateElement("script");
    IHTMLScriptElement myScriptElement = (IHTMLScriptElement)scriptEl.DomElement;
    myScriptElement.src = @"file:///c:\JScript.js";
    head.AppendChild(scriptEl);
}

how you can see first is reference to jQuery because I use it in my script. When I try to invoke function from my script using _webBrowser.Document.InvokeScript WebBrowser throws Script Error :"Object expected"开发者_如何学运维. and points to the line where i try to use jQuery (var tags = $("Body").find("*");).

How can I prevent this error?

Another interesting thing: if I add something like alert("hello"); to start of my function all works fine.

Haven't got correct answer, but have solved the problem by using local copy of jquery.min.js.

It's possible you aren't specifying your script to run on load. alert("hello") is buying that time needed to download the script/finish building the HTML.

$(document).ready(function() {
  // Handler for .ready() called.
});