Update UI and catch executeScript errors now shown in Canary

go-back-with-backspace/pages/options.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.
 
+// Disable the whitelist field when it's not relevant.
+function updateEnabledInputs() {
+  $('whitelist').disabled = !$('disableInApplets').checked;
+}
+
 // Initialize the page.
 function init() {
-  LoadInternationalizedStrings();
-
-  var blacklist = document.getElementById('blacklist');
-  var checkbox = document.getElementById('disableInApplets');
-  var whitelist = document.getElementById('whitelist');
+  loadInternationalizedStrings();
 
   // Configure the textboxes, allowing 200 characters for JSON serialization
   // and key length.
-  blacklist.maxlength = chrome.storage.sync.QUOTA_BYTES_PER_ITEM - 200;
-  whitelist.maxlength = chrome.storage.sync.QUOTA_BYTES_PER_ITEM - 200;
+  $('blacklist').maxlength = chrome.storage.sync.QUOTA_BYTES_PER_ITEM - 200;
+  $('whitelist').maxlength = chrome.storage.sync.QUOTA_BYTES_PER_ITEM - 200;
 
   // Set event handlers.
-  document.getElementById('done_button').onclick = function() {
+  $('done-button').onclick = function() {
     chrome.storage.sync.set({
       // Split the lists into arrays at whitespace before saving.
-      blacklist:
-          document.getElementById('blacklist').value.split(/\s+/),
-      disableInApplets: document.getElementById('disableInApplets').checked,
-      whitelist:
-          document.getElementById('whitelist').value.split(/\s+/)
+      // TODO: Validate the items as URLs and display a warning in case of
+      // errors.
+      blacklist: $('blacklist').value.split(/\s+/),
+      disableInApplets: $('disableInApplets').checked,
+      whitelist: $('whitelist').value.split(/\s+/)
     }, function() {
       // One easy way to force an error for testing is to change "sync" to
       // "managed" in the chrome.storage.sync.set() call above.
       if (chrome.runtime.lastError) {
-        document.getElementById('error').textContent =
+        $('error').textContent =
             chrome.i18n.getMessage('errorSaving',
                                    chrome.runtime.lastError.message);
       } else {
         window.close();
       }
     });
   };
 
-  document.getElementById('cancel_button').onclick = function() {
-    window.close();
-  };
-
-  document.getElementById('report_page').onclick = function() {
-    reportPage();
+  $('disableInApplets').onchange = updateEnabledInputs;
+  $('cancel-button').onclick = window.close.bind(window);
+  $('feedback-link').onclick = function() {
+    sendFeedback();
   };
 
   // Load saved settings into the form fields.
   chrome.storage.sync.get({
     blacklist: [],
     disableInApplets: true,
     whitelist: []
   }, function(items) {
-    blacklist.value = items.blacklist.join('\n');
-    checkbox.checked = items.disableInApplets;
-    whitelist.value = items.whitelist.join('\n');
+    $('blacklist').value = items.blacklist.join('\n');
+    $('disableInApplets').checked = items.disableInApplets;
+    $('whitelist').value = items.whitelist.join('\n');
+
+    updateEnabledInputs();
   });
 }
 
-window.addEventListener('load', init, false);
+window.addEventListener('load', init);