Autocomplete disallow free text entry?

Question

Is it possible to disallow free text entry in the JQuery UI autocomplete widget?

eg I only want the user to be allowed to select from the list of items that are pre

Answer 1

According to the API documentation, the change event's ui property is null if the entry was not chosen from the list, so you can disallow free text as simply as this:

$('#selector').autocomplete({
    source: url,
    minlength: 2,
    change: function(event, ui) {
        if (ui.item == null) {
          event.currentTarget.value = ''; 
          event.currentTarget.focus();
        }
    }
});