http://www.portalaska.com/combo.html
http://www.portalaska.com/combo.js
Here is a very basic simulated editable combo box for quick and dirty uses.
After any text input on a form you simply add a...
<script>fancycombo("[inputid]combo","[inputid]","[option1]","[option2]","[option3]")</script>
You must give the input an id as well as a name. They don't have to be the same thing, but its recommended.
NS broke when I was cleaning up the code. Searching for the error.