Update UI and catch executeScript errors now shown in Canary

go-back-with-backspace/pages/popup.js

 // Copyright 2016 Google Inc. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Return true if the extension is permitted to run on the given URL, with
 // the indicated permission for file:// schemes.
 function urlAllowed(url, file_ok) {
   // Extensions are prohibited on the Chrome Web Store.
   if (url.startsWith('https://chrome.google.com/webstore/'))
     return false;
 
   // Extensions are permitted to run on pages with schemes http, https, and
   // ftp, plus file if enabled.
   if (url.startsWith('http://') ||
       url.startsWith('https://') ||
       url.startsWith('ftp://'))
     return true;
 
   if (file_ok && url.startsWith('file://'))
     return true;
 
   return false;
 }
 
 // Update the popup display depending on the current options and the URL of
 // the current page.
 function updatePopup(options, url) {
-  var button = document.getElementById('list_edit_button');
+  var button = $('list-edit-button');
 
   if (!urlAllowed(url, options.file_ok)) {
     button.textContent = chrome.i18n.getMessage('popupAddBlacklist');
     button.disabled = true;
     setStatusError('popupDisallowedURL');
   } else if (options.blacklist.includes(url)) {
     button.textContent = chrome.i18n.getMessage('popupRemoveBlacklist');
   } else {
     button.textContent = chrome.i18n.getMessage('popupAddBlacklist');
   }
 
   // If the current page is prohibited because it's a file:// scheme, show a
   // link to chrome://extensions, where that setting can be changed.
   if (!options.file_ok && url.startsWith('file://')) {
-    document.getElementById('file_url_message').hidden = false;
-    document.getElementById('status').hidden = true;
+    $('file-url-message').hidden = false;
+    $('status').hidden = true;
   }
 }
 
 // Set the status text and display it in the error style.
 function setStatusError(message_id, placeholder) {
   setStatus(message_id, placeholder);
-  document.getElementById('status').classList.add('error');
+  $('status').classList.add('error');
 }
 
 // Set the status text.
 function setStatus(message_id, placeholder) {
-  var status = document.getElementById('status');
   if (placeholder === undefined)
-    status.textContent = chrome.i18n.getMessage(message_id);
+    $('status').textContent = chrome.i18n.getMessage(message_id);
   else
-    status.textContent = chrome.i18n.getMessage(message_id, placeholder);
+    $('status').textContent = chrome.i18n.getMessage(message_id, placeholder);
 }
 
 // Initialize the page.
 function init() {
-  LoadInternationalizedStrings();
+  loadInternationalizedStrings();
 
   // Load the active tab's URL, then set up page features that depend on it.
   chrome.tabs.query({active: true, currentWindow: true}, function(tabList) {
     var url = tabList[0].url;
-    var element = document.getElementById('current_url');
-    element.textContent = chrome.i18n.getMessage('popupCurrentURL', url);
 
     // Load settings.
     var options = {};
     chrome.storage.sync.get({
       blacklist: [],
       disableInApplets: true,
       whitelist: []
     }, function(items) {
       options = items;
       // Read the extension file-access permission and update the popup UI.
       chrome.extension.isAllowedFileSchemeAccess(function(file_ok) {
         options.file_ok = file_ok;
         updatePopup(options, url);
       });
     });
 
     // Set event handlers that depend on the URL.
-    document.getElementById('list_edit_button').onclick = function() {
+    $('list-edit-button').onclick = function() {
       var index = options.blacklist.indexOf(url);
       if (index > -1)
         options.blacklist.splice(index, 1);
       else
         options.blacklist.push(url);
 
       chrome.storage.sync.set({
         blacklist: options.blacklist,
         whitelist: options.whitelist
       }, function() {
         if (chrome.runtime.lastError) {
           setStatusError('errorSaving', chrome.runtime.lastError.message);
         } else {
           updatePopup(options, url);
           setStatus('popupStatusSaved');
         }
       });
     };
 
-    document.getElementById('report_page').onclick = function() {
-      reportPage(url);
+    $('feedback-link').onclick = function() {
+      sendFeedback(url);
     };
   });
 
   // Set event handlers that don't need the URL.
-  document.getElementById('open_options').onclick = function() {
+  $('options-link').onclick = function() {
     chrome.runtime.openOptionsPage();
   };
 
-  document.getElementById('open_extensions').onclick = function() {
+  $('open-extensions').onclick = function() {
     chrome.tabs.create({url: 'chrome://extensions', active:true});
     window.close();
   };
 }
 
-window.addEventListener('load', init, false);
+window.addEventListener('load', init);