Here's one, quick n' easy:
- Code: Select all
<style type="text/css">
#menu1 { border: 1px solid #000; width: 120px; }
#items1 { overflow:hidden; height:0px; }
</style>
<div id="menu1" onmouseover="document.getElementById('items1').style.height='auto';" onmouseout="document.getElementById('items1').style.height='0px';">
Menu Header
<div id="items1">
<a href="#">a blah</a><br />
<a href="#">b blah</a><br />
<a href="#">c blah</a><br />
</div>
</div>
Works in Mozilla, IE and Opera

{Edit}
After playing around with the code for a bit Opera seems to like this:
- Code: Select all
<style type="text/css">
.menu { border: 1px solid #000; width: 120px; }
.items { overflow:hidden; height:0px; }
.menu:hover .items { height: auto; }
</style>
<div class="menu">
Menu Header
<div class="items">
<a href="#">a blah</a><br />
<a href="#">b blah</a><br />
<a href="#">c blah</a><br />
</div>
</div>
But non of the other browsers do
