Detecting jQuery UI autocomplete

How can I detect whether or not an input box is currently a jQuery UI autocomplete? There doesn't seem to be a native method for this, but I'm hoping there is something simple like this:

if ($("#q").autocomplete)
{
  //Do something
}

That conditional, however, seems to always return true.

From stackoverflow

• It's true because once you've included the autocomplete js, every $() object now has a autocomplete() method defined (in case you want to activate autocomplete for those elements). Your if() is just saying that that function is not null.

  I, unfortunately don't have a system where I can check this (left the laptop home today), but I believe autocomplete adds a css class name to the elements it's using. You could look for that.

• if ($("#q").hasClass("ac_input")) {
      // do something
  }
  

• You can use

  if( $.isFunction( $.fn.autocomplete ) ){ }
  

  .isFunction is part of the jQuery lib. (cite: http://james.padolsey.com/jquery/....isFunction)