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() {
+  var checkbox = document.getElementById('disableInApplets');
+  document.getElementById('whitelist').disabled = !checkbox.checked;
+}
+
 // Initialize the page.
 function init() {
   LoadInternationalizedStrings();
 
   var blacklist = document.getElementById('blacklist');
   var checkbox = document.getElementById('disableInApplets');
   var whitelist = document.getElementById('whitelist');
 
   // Configure the textboxes, allowing 200 characters for JSON serialization
   // and key length.
@@ skipping 15 matching lines @@
       if (chrome.runtime.lastError) {
         document.getElementById('error').textContent =
             chrome.i18n.getMessage('errorSaving',
                                    chrome.runtime.lastError.message);
       } else {
         window.close();
       }
     });
   };
 
+  checkbox.onchange = updateEnabledInputs;
+
   document.getElementById('cancel_button').onclick = function() {
     window.close();
   };
 
   document.getElementById('report_page').onclick = function() {
     reportPage();
   };
 
   // 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');
+
+    updateEnabledInputs();
   });
 }
 
 window.addEventListener('load', init, false);