How to use remote source with jquery ui combobox?

Question

There is combobox with autocomplete enabled. How to pass JSON data as source for this combobox?

Upd. I\'ve found partial answer here - it allows me

Answer 1

Here is the working example - http://jsfiddle.net/and7ey/TFerw/3/

Remote end should return some values (most popular) in case when empty term is requested - it happens when user presses combobox button.