title: How to select a div id in firebug command?
body: <p>I have a html defined like this:</p>
  
  <pre><code>&lt;!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
          "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt;
  &lt;html&gt;
  &lt;head&gt;
  ...
  &lt;/head&gt;    
  &lt;body&gt;
  &lt;div id="nav"&gt;
      &lt;a href="/"&gt;home&lt;/a&gt; |
      {% if user.is_authenticated %}      
          &lt;a href="/save/"&gt;submit&lt;/a&gt; | &lt;a href="/user/{{ user.username}}/"{{ user.username }}&lt;/a&gt; | &lt;a href="/logout/"&gt;logout&lt;/a&gt;
      {% else %}
            &lt;a href="/login"&gt;login&lt;/a&gt; | &lt;a href="/register/"&gt;register&lt;/a&gt;    
      {% endif %}
  &lt;/div&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>In Firebug Console I type the following to hide the nav class:</p>
  
  <pre><code>$("#nav").hide()
  </code></pre>
  
  <p>But when I run it I get this error message:</p>
  
  <pre><code>TypeError: $("#nav") is null
  
  $("#nav").hide()     with(_...e() }; (line 2)
  </code></pre>
  
  <p>nav is clearly there, I can even see it in the HTML tab of Firebug, what am I missing?</p>
  
  <p>Thanks</p>