I began learning Javascript today with Sitepoints Simply JavaScript. Everything was going great until I got to page 69 and I was not getting an alert dialog for the following code:

var target = document.getElementById("berenger");

the html file looks like:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
<html xmlns="http://www.w3.org/1999/xhtml" lang="en-US">
<title>The Running Man</title>
<meta http-equiv="Content-Type"
content="text/html; charset=utf-8" />
<script type="text/javascript" src="example.js"></script>
Sniper (1993)
<p>In this cinema materpiece,
<a id="berenger" href="/name/nm0000297/">Tom Berenger</a> plays
a US soldier working in the Panamanian jungle.</p>

It didn't even return a null value. Please help.