windowPopUp = function(url){
	var t = new Number((screen.height/2)-(487/2)); 
	var l = new Number(((screen.width/2)-(768/2)));
	window.open( url, '_blank', 'width=768,height=487,top='+t+',left='+l+',menubar=no, resizable=no,status=no,scrollbars=no,titlebar=no,toolbar=no');
}