x.js

CmdUtils.CreateCommand({
    name: "moo",
    description: "test moo",
    preview: function(pblock, statusText) {
        CmdUtils.injectJavascript("http://ajax.googleapis.com/ajax/libs/mootools/1.2.4/mootools-yui-compressed.js";,
            Utils.safeWrapper(function() {
                pblock.innerHTML = MooTools;
            })
        );
    },
    execute: function(statusText) {}
});