function popUp(myform, windowname) 
{ 
  if (! window.focus)return true; 
  var h = 800; 
  var w = 500; 
  var text; 
  if (document.all || document.layers) { 
    w = screen.availWidth; 
    h = screen.availHeight; 
  } 
  var popW = 628; 
  var popH = 420; 
  var lefPos = (w-popW)/2; 
  var topPos = (h-popH)/2;          text='toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resizable=no,height='+popH+',width='+popW+',top='+topPos+',left='+lefPos 
// window.open('images/large/310.html', windowname, text);
window.open(myform, windowname, text); 
  myform.target=windowname; 
//  return true; 
}