Sorting and Editing Dropdown Combo

hi frnds,

I have to implement a dropdown -without using ajax...in vs2.0 (vb.net-WEB APPLICATION)
sorting should be done..
ie,if u enter A it should show the words starts with A.

If u enter AP ,it should show words start with AP etc.
and the dropdown data should be editable.

so, how to implement this

Thanks in advance

[url]http://www.geekinterview.com/talk/7117-dropdown.html[/url]