function getScreenWidth()
{
    return window.screen.availWidth;
}

function getScreenHeight()
{
    return window.screen.availHeight;
}

function windowOpenPopup(url, name, width, height)
{
    var left = (getScreenWidth()-width)/2;
    var top = (getScreenHeight()-height)/2;
    width+=0;
    height+=0;
    wId=window.open(url, name, 'toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resizable=no,left='+left+',top='+top+',width='+width+',height='+height);
    wId.focus();
    return wId;
}