function openPopUp(url) { 
 var width = 400;
 var height = 300;
 var left = (screen.availWidth/2) - (width/2);
 var top = (screen.availHeight/2) - (height/2);
 var windowFeatures = ",width=" + width + ",height=" + height
 					+ ",resizable,toolbar=no,menubar=no,location=no,scrollbars=no"
 					+ ",left=" + left + ",top=" + top
 					+ ",screenX=" + left + ",screenY=" + top;
 var thisWindow=window.open(url, "popup", windowFeatures);
}