Reset element to "default" event
<p>In Javascript, how can you set the event handler of a DOM element to default behavior?</p>

<p>For example, suppose I set the <code>onkeypress</code> event of an input element:</p>

<pre><code>elem.onkeypress = function() { alert("Key pressed!"); }
</code></pre>

<p>Later, how can I remove this event?  Is it okay to simply set the <code>onkeypress</code> property to null?  I tried that and it works, but I don't know if it is the proper way to do this.</p>
