var windowHandle = null;
var windowHandle_closed = false;

function openWindow(url,width,height) {
    windowHandle = window.open(url, '', 'toolbar=no,location=no,directories=no,status=yes,menubar=no,scrollbars=no,resizable=no,left=' + ((screen.width/2+60)-width/2) + ',top=' + 50 + ',width=' + width + ',height=' + height);
    if (windowHandle_closed == true) {
        windowHandle_closed = false;
    }
}

function closeWindow() {
    if (windowHandle != null) {
        if (!windowHandle_closed) {
            windowHandle_closed = true;
            if (windowHandle.close) {
                windowHandle.close();
            }
        }
    }
}