how to check if autocomplete is closed?

how to check if autocomplete is closed?

How can I check if autocomplete is closed in this section of the code below 
if (e.which == 13) ?

 <div class="ui-widget"> <label for="tags">Tags: </label> <input id="tags" /> </div>

var sectionAdata = ["ActionScript","AppleScript","Asp"];

 $("#tags").on('keyup', function (e) {
 	if(e.which == 13) alert("send to section B" + this.value);
 }).autocomplete({
 	source: availableTags,
 	select: function (event, ui) {}
 });