function isSilverlightInstalled()
{
    var isSilverlightInstalled = false;
    try
    {
        //check on IE
        try
        {
            var slControl = new ActiveXObject('AgControl.AgControl');
            isSilverlightInstalled = true;
        }
        catch (e)
        {
            //either not installed or not IE. Check Firefox
            if ( navigator.plugins["Silverlight Plug-In"] )
            {
                isSilverlightInstalled = true;
            }
        }
    }
    catch (e)
    {
       //we don't want to leak exceptions. However, you may want
       //to add exception tracking code here.
    }
    var windid = window.open("/espunautils/sessionUtil.aspx?slinstalled="+isSilverlightInstalled);
    windid = null;
}