function buildurl(url, argname, argvalue)
{
    if (url.indexOf('?') != -1)
        url = url + '&';
    else
        url = url + '?';
    url = url + argname + '=' + argvalue;
    return url;
}

function zwp_select_all(class_name)
{
    var select = xGetElementById(class_name);
    select = select.checked;
    var a = xGetElementsByClassName(class_name, null, "input", null);
    for (var i in a)
        a[i].checked = select;
}