HTMLScriptCollection scriptCollection = new HTMLScriptCollection(); 
HTMLScript script = new HTMLScript("text/javascript"); 
scriptCollection.AddInnerHTMLElement(script); 
script.AddInnerHTMLString("function myTest() { alert('test'); }"); 
AddJavascript(scriptCollection);

To include common JavaScript that can be shared between multiple instances of a tag (i.e. JavaScript that is displayed once per page, regardless of how many tags of a certain type there are), override the DisplaySharedJavascript method. DisplaySharedJavaScript is called automatically by the framework.

/** 
* Adds the PTIncluder object to the client.  This object is used for 
* retrieving JSComponent client classes from a page. 
*/ 
public HTMLScriptCollection DisplaySharedJavascript() 
{ 
HTMLScriptCollection result = new HTMLScriptCollection(); 
HTMLScript script = new HTMLScript("text/javascript"); 
result.AddInnerHTMLElement(script); script.SetSrc("/myjsfile.js"); 
return result; 
}

If there are errors in the tag and the JavaScript cannot be displayed properly, the tag should throw an XPException with an error message, and the tag framework will log the error and add the message and stack trace to the HTML as an HTML comment. The message contents will be HTML encoded before being added to the comment.