I am just using autocomplete for the first time and tried the code below.  But ...

In the "select;" below, the ui.item.value displays correctly but the ui.item.id displays "undefined".  

Why doesn't the "ui.item.id" display either "Test1" or "Test2". 

Thanks

    $(document).ready(function() {

        $("#<%= autocomplete.ClientID %>").autocomplete({

        source: [{ "value": "Test1val", "label": "Test1" }, { "value": "Test2val", "label": "Test2"}]

        ,

        select: function(event, ui) {alert("Selected: " + ui.item.value + " aka " + ui.item.id); }

        });

    });