title: drop down menu in html5
body: <p>i have the following code which has navigation, i want to add sub menu/drop down to them. (say a drop down from categories). how should i implement that? please help</p>
  
  <pre><code>&lt;nav&gt;
      &lt;div class="navbutton"&gt;&lt;a href="..."&gt;contact us &lt;/a&gt;&lt;/div&gt;
      &lt;!-- &lt;div class="navbutton"&gt;&lt;a href="..."&gt;forum &lt;/a&gt;&lt;/div&gt;--&gt;
      &lt;div class="navbutton"&gt;&lt;a href="#"&gt;Categories&lt;/a&gt;&lt;/div&gt;
      &lt;div class="navbutton"&gt;&lt;a href="Register.html"&gt;Register &lt;/a&gt;&lt;/div&gt;
      &lt;div class="navbutton"&gt;&lt;a href="..."&gt;About Us &lt;/a&gt;&lt;/div&gt;
      &lt;div class="navbutton"&gt;&lt;a href="..."&gt;Home Page &lt;/a&gt;&lt;/div&gt;           
  &lt;/nav&gt;
  </code></pre>