background.js

// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// I did not modify this script since it worked well to get information from
// the requested page.

/**
 * Handles requests sent by the content script.  Shows an infobar.
 */
function onRequest(request, sender, sendResponse) {
  // The number of matches is sent in the request - pass it to the
  // infobar.
  var url = "infobar.html#" + request.pageScore;

  // Show the infobar on the tab where the request was sent.
  chrome.infobars.show({
    tabId: sender.tab.id,
    path: url
  });

  // Return nothing to let the connection be cleaned up.
  sendResponse({});
};

// Listen for the content script to send a message to the background page.
chrome.extension.onRequest.addListener(onRequest);