Check for mouseenter after page is loaded
<p>One of my elements has a <code>mouseenter</code> event on it. The trouble is, I can't add the event until the dom is fully loaded, so I use something like:</p>

<pre><code>document.observe('dom:loaded', function() {
    ${"my_element").observe("mouseenter", function() { ... }
});
</code></pre>

<p>Now, the user might be mousing over the element before the page is fully loaded, and so the event doesn't fire. They have to move their mouse to have it fire. How can I detect if I should fire the event after the page is fully loaded, so the user doesn't have to move their mouse?</p>
