HTTPのレスポンスを取得

function hello(){

  var uri = Components.classes["@mozilla.org/network/standard-url;1"]

    .createInstance(Components.interfaces.nsIURI);

  uri.spec = "http://www.google.com/";
  var ios = Components.classes["@mozilla.org/network/io-service;1"]

    .getService( Components.interfaces.nsIIOService );

  var channel = ios.newChannelFromURI(uri);
  var observer = {

    onStreamComplete: function(loader, cx, status, len, result) {

      alert(String.fromCharCode.apply(this, result));

    }

  };


  var sl = Components.classes["@mozilla.org/network/stream-loader;1"]

    .createInstance(Components.interfaces.nsIStreamLoader);
  sl.init(channel, observer, null);

}