Populating a Combo Box Dynamically with an AJAX Call

[Bob OD]

I am rather new to the toolkit so this may be a stupid question, but I am looking to populate a combo box with items from an AJAX call. The thought is the combo box will start off empty and based on what the user types in, I will populate the combo box with valid selections. The code calls a web service which returns XML which is then converted via JavaScript to JSON. I then want to use those JSON values to populate the list. Thoughts? thanks.