Automatically changes the font to Meiryo for the chosen domains.

automeiryo

// ==UserScript==
// @name       Auto-Meiryo
// @namespace  http://use.i.E.your.homepage/
// @version    0.1
// @description  enter something useful
// @copyright  2012+, You
// ==/UserScript==

(function() {
    var always = 'alwaysHost';

    function styleMeiryo() {
        var style = document.createElement('style');
        style.textContent = '*{font-family:Meiryo !important;}';
        document.body.appendChild(style);
    }

    function hasHost() {
        return GM_getValue(always, []).indexOf(location.host) !== -1;
    }

    function addHost() {
        var hosts = GM_getValue(always, []);
        hosts.push(location.host);
        GM_setValue(always, hosts);
    }

    function removeHost() {
        var hosts = GM_getValue(always, []);
        hosts.splice(hosts.indexOf(location.host), 1);
        GM_setValue(always, hosts);
    }

    if (hasHost()) {
        styleMeiryo();
        GM_registerMenuCommand('Meiryo auto-styler: remove ' + location.host, function() {
            removeHost();
        });
    }
    else {
        GM_registerMenuCommand('Meiryo auto-styler: add ' + location.host, function() {
            addHost();
            styleMeiryo();
        });
    }
}());