title: javascript highlight a string
body: <p><code>var str = 'test TEST';</code></p>
  
  <p>How to get <code>str</code> = '<code>&lt;span class="red"&gt;test&lt;/span&gt; &lt;span class="red"&gt;TEST&lt;/span&gt;</code>' in return.</p>
  
  <p>Thanks a lot.</p>