window.onbeforeunload=ClearCookie;
ClearCookie=true;
function CheckNewWindow()
{
   if (document.cookie.indexOf("SessionIdentifier" + SessionIdentifier)>-1)
   {
      ClearCookie=false;
	  if (navigator.userAgent.toLowerCase().indexOf('msie') > -1 ||
		navigator.userAgent.toLowerCase().indexOf('gecko') > -1)
	  {
		GenerateNewSession();
	  }
      return;
   }
   document.cookie = "SessionIdentifier" + SessionIdentifier + "=123456";
}

function ClearCookie()
{
	if (ClearCookie)
		document.cookie = "SessionIdentifier" + SessionIdentifier + "=123456; expires=Fri, 31 Dec 1999 23:59:59 GMT;";
}