function openCenteredWindow(url, width, height) {
    var left = parseInt((screen.availWidth/2) - (width/2));
    var top = parseInt((screen.availHeight/2) - (height/2));
	
    var windowFeatures = "width=" + width + ",height=" + height + ",status=no,resizable=no,scrollbars=no,menubar=no,left=" + left + ",top=" + top + "screenX=" + left + ",screenY=" + top;
    window.open(url, '', windowFeatures);
	return false;
}