Выделить код

Код:

var historyService = Components.classes["@mozilla.org/browser/global-history;2"]
    .getService(Components.interfaces.nsIGlobalHistory2);

var ioService = Components.classes["@mozilla.org/network/io-service;1"]
    .getService(Components.interfaces.nsIIOService);

alert(
    historyService.isVisited(ioService.newURI("http://ya.ru", null, null))
    );