Calling a JavaScript function from Silverlight 2
Wow, this is far better now with SL2! no more tips and tricks.
BLOCKED SCRIPT
<script type="text/javascript">
function DisplayMessage()
{
alert("call me from Silverlight 2");
}
</script>
Silverlight:
using System.Web.Browser;
HtmlPage.Window.CreateInstance("DisplayMessage");

Read the complete post at http://weblogs.asp.net/lduveau/archive/2008/03/26/calling-a-javascript-function-from-silverlight-2.aspx