ui/accessibility/extensions/longdesc/background.js

   1 /* Copyright (c) 2014 The Chromium Authors. All rights reserved.
   2  * Use of this source code is governed by a BSD-style license that can be
   3  * found in the LICENSE file. */
   4
   5 var ariaDescribedAt = '';
   6 var longDesc = '';
   7
   8  /**
   9  * This is called when the extension is first loaded, so that it can be
  10  * immediately used in all already-open tabs. It's not needed for any
  11  * new tabs that open after that, the content script will be automatically
  12  * injected into any new tab.
  13  */
  14 chrome.windows.getAll({'populate': true}, function(windows) {
  15   for (var i = 0; i < windows.length; i++) {
  16     var tabs = windows[i].tabs;
  17     for (var j = 0; j < tabs.length; j++) {
  18       try {
  19         chrome.tabs.insertCSS(
  20           tabs[j].id,
  21           {file: 'border.css'},
  22           function(result) {
  23             chrome.runtime.lastError;
  24           });
  25       } catch (x) {
  26       }
  27       try {
  28         chrome.tabs.executeScript(
  29           tabs[j].id,
  30           {file: 'lastRightClick.js'},
  31           function(result) {
  32             chrome.runtime.lastError;
  33           });
  34       } catch (x) {
  35       }
  36     }
  37   }
  38 });
  39
  40 /**
  41  * Add context menu item when the extension is installed.
  42  */
  43 chrome.contextMenus.create({
  44     "title": chrome.i18n.getMessage('longdesc_context_menu_item'),
  45     "contexts": ["all"],
  46     "id": "moreInfo",
  47     "onclick": contextMenuClicked,
  48     "enabled": false
  49   });
  50
  51 /**
  52  * Add listener for messages from content script.
  53  * Enable/disable the context menu item.
  54  */
  55 chrome.runtime.onMessage.addListener(
  56   function (request, sender, sendResponse) {
  57     if (request.enabled) {
  58       ariaDescribedAt = request.ariaDescribedAt;
  59       longDesc = request.longDesc;
  60     }
  61     chrome.contextMenus.update('moreInfo', {
  62       "enabled": request.enabled
  63     });
  64   });
  65
  66 /**
  67  * Event handler for when a context menu item is clicked.
  68  * aria-describedat is given a higher priority.
  69  * No need to strip the URL of leading/trailing white space
  70  * because Chrome takes care of this.
  71  *
  72  * @param info
  73  * @param tab
  74  */
  75 function contextMenuClicked(info, tab) {
  76   if (ariaDescribedAt !== '') {
  77     chrome.tabs.create({url: ariaDescribedAt});
  78   } else if (longDesc !== '') {
  79     chrome.tabs.create({url: longDesc});
  80   }
  81 }