Combobox

Momentarily i am making a checklist
I want to make a combobox Yes/No

I already made this, but i was wandering this:
Is it possible that, when entered Yes, more text revealed, and when entered No, this text will vanish?

I've got an example of it in the document but can't upload it

Hope someone can help me out.
grtz

Edit: Never mind, i don't need it anymore