function openCenteredWindow(url, width, height) {
        var width = width;
        var height = 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, menubar=no, resizable=no, scrollbars=no, toolbar=no, location=no, directories=no,left=" + left + ",top=" + top + "screenX=" + left + ",screenY=" + top;
        window.open(url, "subWind", windowFeatures);
    }