function open_window(URL,NAME,HEIGHT,WIDTH) {
   if (document.all) {
   	var xMax = screen.width, yMax = screen.height;
   } else {
   	if (document.layers) {
   		var xMax = window.outerWidth, yMax = window.outerHeight;
   	} else {
   		var xMax = 640, yMax = 480;
   	}
   }

   var xOffset = (xMax - 200)/2;
   var yOffset = (yMax - 200)/2;
   var url = URL;
   var winname = NAME;
   var options;
   options = 'toolbar=no,scrollbars=yes,height=' + HEIGHT + ',width=' + WIDTH + ',menubar=yes,resizable=yes,status=no';
   options += ',top=0,left=0';
   //options += ',top='+yOffset+',left='+xOffset;
   new_window = window.open(url,winname,options);
}