How can I create an editable combobox?

I need to populate the combo box Items from a database query (this part is no problem). Then if the user does not find an option, they can enter their own text and store in Db with index.. Add new item to store in Db with index开发者_如何学Go value and display the value from db with index and value.

using jquery or javascript...

Help plz..

Actually there is a plugin called jEC

Product Page

Demo

jEC on Google Code