Dropdown navigations still seem to be cool and are part of almost every screen design these days. The fact that they cause a lot of accessibility and usability issues seems not to transpire, and clients keep asking for them. The amount of badly written, obstrusive, and bloated scripts is staggering. There are some very good ones though (Son of suckerfish, aqTree2, Gazingus), so why another one?
Why You Might Want to Use YADM
YADM was created with the following ideas in mind:
Mouse Independence - By applying the functionality when clicking and when hovering over the item keyboard users can also reach the nested menus, something that cannot be done in CSS-only solutions
Easy restyling - The look is maintained exclusively in CSS, YADM applies different classes to the markup to achieve that.
Browser independence - Although some browsers may behave oddly (Opera still has issues updating the screen, resulting in half-visible menus), the script does not sniff or check for any browser - just for objects.