Update UI and catch executeScript errors now shown in Canary

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

Index: go-back-with-backspace/pages/options.js
diff --git a/go-back-with-backspace/pages/options.js b/go-back-with-backspace/pages/options.js
index 9ff25d65f1c7564e76834ea643093fd4fa7893ba..b95b45f66b6b7902bab6d9af2a71e97a57060008 100644
--- a/go-back-with-backspace/pages/options.js
+++ b/go-back-with-backspace/pages/options.js
@@ -2,6 +2,12 @@
 // 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();
@@ -37,6 +43,8 @@ function init() {
     });
   };
 
+  checkbox.onchange = updateEnabledInputs;
+
   document.getElementById('cancel_button').onclick = function() {
     window.close();
   };
@@ -54,6 +62,8 @@ function init() {
     blacklist.value = items.blacklist.join('\n');
     checkbox.checked = items.disableInApplets;
     whitelist.value = items.whitelist.join('\n');
+
+    updateEnabledInputs();
   });
 }