function popUp(url, name, param) {
    var popUp;

    popUp = window.open(url, name, param);
    if (popUp == null) {
        return null;
    }
    else {
        popUp.focus();
        return popUp;
    }
}

function OpenCredits(url, target) {

    leftVal = (screen.width - 450) / 2;
    topVal = (screen.height - 130) / 2;

    popUp(url, target, "width=450,height=130,left=" + leftVal +
                     ",top=" + topVal + ",scrollbars=no,resizable=no,status=no");

    return false;
}