function change_sort(t) {
    var url = location.href;
    if(url.search(/t=/) < 0) {
        if(url.search(/.php\?/) < 0) 
            location.href = url + "?t=" + t;
        else
            location.href = url + "&t=" + t;
    } else {
        url = url.replace(/t=\d+/, "t="+t);
        location.href = url;
    }
    return false;
}