function popupWindow(url,wwidth,wheight) 
	{
		 var left   = (screen.width  - wwidth)/2;
		 var top    = (screen.height - wheight)/2;
		 var params = 'width='+wwidth+', height='+wheight;
		 params += ', top='+top+', left='+left;
		 params += ', directories=no';
		 params += ', location=no';
		 params += ', menubar=no';
		 params += ', resizable=yes';
		 params += ', scrollbars=yes';
		 params += ', status=no';
		 params += ', toolbar=no';
		 newwin=window.open(url,'', params);
		 if (window.focus) {newwin.focus()}
		 return false;
	}