1. Put the following code to your theme footer.php within <body></body> tag:
* Or you could put the code to header tag (header.php) if you wanna load it earlier than this.
2. When you wanna highlight a code, switch to text view in WordPress editor, and put your code snippets inside of a “pre” tag: <pre class=”prettyprint”>//code here</pre>
Or a “code” tag: <code class=”prettyprint”>//code here</code>
The result should look like this(Notice that the line number appears in every fifth line by default):