autocomplete form input

I have a form that contains a jquery autocomplete field with a combobox per the example ( http://jqueryui.com/demos/autocomplete/#combobox). I'm now trying to submit the form and use the submitted value. However, when I inspect the form using Firebug, I don't see the input field in the form. Any thoughts?

I can see the combobox element as well as my other form elements.