var myWindow;
function openCenteredWindow(url) {
    var width = 400;
    var height = 430;
    var left = parseInt((screen.availWidth / 2) - (width / 2));
    var top = parseInt((screen.availHeight / 2) - (height / 2));
    var windowFeatures = "width=" + width + ",height=" + height + ",status,resizable='false',left=" + left + ",top=" + top + "screenX=" + left + ",screenY=" + top;
    myWindow = window.open(url, "subWind", windowFeatures);
}