Googleの検索言語切り替え(en<->ja)ブックマークレット

ggrks_switch_lang.js

javascript:void((function () {
    var url = location.href;
    var ja = url.search(/hl=ja/);
    var en = url.search(/hl=en/);

    if (url.search(/google\.(co\.jp|com)\/search/) < 0) return;

    if (ja > 0) {
        location.href = url.replace(/hl=ja/, "hl=en");
    } else if (en > 0) {
        location.href = url.replace(/hl=en/, "hl=ja");
    } else {
        var beginning_of_params = url.search(/\?/) + 1;
        location.href = url.substr(0, beginning_of_params) + "hl=ja&" + url.substr(beginning_of_params);
    }
})());