Add another class to a div with javascript
<p>I have a function that checks the age of a form submission and then returns new content in a div depending on their age.  right now I am just using getElementById to replace the html content.  BUt I think would work better for me if I could also add a class to a div as well.  So for example I have..</p>

<pre><code>if (under certain age) {
    document.getElementById('hello').innerHTML = "&lt;p&gt;Good Bye&lt;/p&gt;"; 
    createCookie('age','not13',0)
    return false;
} else {
    document.getElementById('hello').innerHTML = "&lt;p&gt;Hello&lt;/p&gt;";  
    return true;
}
</code></pre>

<p>What I would like to do is have everything in a div and if return false then that div disappears and is replaced with other content.. can I get any ideas on a good way to achieve this with pure javascript.  I dont want to use jQuery for this particular function.</p>
