function productPopUp(url,windowname,width,height,features) 
{ 
  width=(width)?width:screen.width/2;
  height=(height)?height:screen.height/2;
  var screenX = (screen.width/2 - width/2);
  var screenY = (screen.height/2 - height/2);
  var features= "width=" + width + ",height=" + height +",scrollbars=no,";
  features += ",screenX=" + screenX + ",left=" + screenX;
  features += ",screenY=" + screenY + ",top=" + screenY;

  var mywin=window.open(url, windowname, features);
  if (mywin) 
  mywin.focus();
  return mywin;
}