Jquery autocomplete mouse selection problem

Question

Hi
If I select data with mouse not updating id associated with the data.

Ex: I'm passing a call back function to

$("#" + elementId).result(function (event, data, value) {
    if (data) {
        $("#userId").val(data.id);
    }else {
        alert("userId is not selected");
    }
});

I'm getting an alert message when I select data using mouse. pls help me.