function winopen(w,h,url,w_name)
{
	var wleft=(screen.width-w)/2;
	var wtop=(screen.height-h)/2;
	window.open(url,w_name,'menubar=no,status=no,scrollbars=no,width='+w+',height='+h+',toolbar=no,location=no,directories=no,left='+wleft+',top='+wtop+'');
}