PH! relative links

// ==UserScript==
// @name            PH! relative links
// @author          arfhelf, cyla
// @version         0.2.1
// @namespace       archelf.ph
// @description     Create relative links from absolute links
// @include         http://prohardver.hu/*
// @include         http://itcafe.hu/*
// @include         http://mobilarena.hu/*
// @include         http://gamepod.hu/*
// @include         http://logout.hu/*
// ==/UserScript==

/*
Versions:
0.1a                Initial release
0.2                 Initial opera release
                    Added includes instead of URLCheck
                    Replace forum links only
                    Replace links with www subdomains
                    Replace rios4 forum links
                    Replace rios3 forum links with rios4 ones
0.2.1               Replace user links
*/

(function(){
    var center = document.getElementById( "center" );
    var anchors = center.getElementsByTagName( "a" );

    for ( var x = 0; x < anchors.length; x++ ) {
        var url = anchors[x].href;
        anchors[x].href = URLTrim( url );
    }
})();

function URLTrim( url ) {
    var sites = Array(
        "http://prohardver.hu/",
        "http://www.prohardver.hu/",
        "http://itcafe.hu/",
        "http://www.itcafe.hu/",
        "http://logout.hu/",
        "http://www.logout.hu/",
        "http://mobilarena.hu/",
        "http://www.mobilarena.hu/",
        "http://gamepod.hu/",
        "http://www.gamepod.hu/"
    );

    for ( var x = 0; x < sites.length; x++ ) {
        if ( ( url.indexOf( sites[x] ) == 0 ) && ( url.length > sites[x].length ) && ( ( url.search( ".hu/tema/" ) != -1 ) || ( url.search( ".hu/tag/" ) != -1 ) || ( url.search( ".hu/f.php" ) != -1 ) || ( url.search( ".hu/rios3_forum.php" ) != -1 ) ) ) {
            url = url.substring( sites[x].length - 1 );

            if ( url.search( "rios3" ) != -1 ) {
                var re = /(.*\/)rios3_forum\.php\?mod=(\d+)\&id=(\d+).*/;
                url = url.replace( re, "$1f.php?mod=$2&id=$3" );
            }
        }
    }

    return url;
}