 function Pcent(w,h,url,n,id) {
   var l = Math.floor((screen.width-w)/2);
   var t = Math.floor((screen.height-h)/2);
      window.open("image.php?n="+n+"&id="+id+"&url="+url+"&w="+w,"","width=" + w + ",height=" + h + ",top=" + t + ",left=" + l+",scrollbars=yes");
 }

