var isNS4 = (document.layers) ? true : false; // NS>=4.0
 var isIE4 = (document.all) ? true : false; // IE>=4.0
 var isW3C = (document.getElementById) ? true : false; // IE>=5.0 & NN>=6.0

 function openForm(id) {
  var width = 240;
  var height = 280;
  var x = window.screen.width;
  var y = window.screen.height;
  var left = (x - width) / 2;
  var top = (y - height) / 2;
  var params = "left=" + left + ",top=" + top + ",width=" + width + ",height=" + height + ",status";
  window.open("form.php","order",params); 
 }