Simple, I thought, just use one of the many existing drop-down plugins. I tried many, but most seemed to use hardcoded styles and I had a few problems (some of which I encountered again, writing this).

So I’ve made this, I think it’s fairly robust, but I’m sure there’ll be problems with embedded objects (flash) and select boxes (in <= IE6), but for my needs, it sufficed, so I thought I'd share, in case anyone else needs a simple script to manage drop-downs.

To use, create a nest of elements like this:

<ul id="top">
  <li>
    <ul>
      <li></li>
    </ul>
  </li>
</ul>

or something similar (any elements, should work) and call:

// jQuery:
$('ul#top').dropdownify();
 
// mootools
$('top').dropdownify();

Which should create a simple drop-down.

There are a couple of examples, one for jQuery and one for mootools, and the files can downloaded here and here.

I did encounter a problem with IE, mainly due to z-index faults, so with HTML code like the following:

<div class="nav-wrapper">
  <ul id="top">
    <li>
      <ul>
        <li></li>
      </ul>
    </li>
  </ul>
</div>

I used the following CSS:

div.nav-wrapper,
div.nav-wrapper ul,
div.nav-wrapper ul li {
  position: static;
  z-index: 100;
}