Listing 5.4: selecting using a *-match on href.

Chapter 5/05.js

@@ -2,7 +2,7 @@
 $(document).ready(function () {
   'use strict';
 
-  $('div.chapter a').attr({
+  $('div.chapter a[href*="wikipedia"]').attr({
     rel: 'external',
     title: 'Learn more at Wikipedia',
     id: function (index, oldValue) {