function markUnmark(numb, markUrl, unmarkUrl)
{
	if (document.images)
	{
		var url_str = document.images['mark'+numb].src ;
		var now = new Date() ;
		var milli = now.getTime() ;
		var img = new Image() ;

		if (url_str.indexOf("/button_mark.gif") != -1 || url_str.indexOf("Unmark") != -1)
		{
		   document.images['mark'+numb].src  = markUrl + "&timestamp=" + milli ;
		}
		else
		{
			document.images['mark'+numb].src  = unmarkUrl + "&timestamp=" + milli ;
		}
	}
}