How to get Id of the selected listitem of dropdown field

Question

I have a dropdown field which is a lookup containing values. I need to get the ID of the selected value whenever we change. I tried using the following. I didnt get any response

$ (document).ready(function(){

$("#ctl00_m_g_8c84c77a_5db3_4a23_9869_d6079afd3bd5_ctl00_ctl05_ctl01_ctl00_ctl00_ctl04_ctl00_Lookup").change(function() { alert("hi"); var id = $(this).find('option:selected').attr('id'); });

alert(id); });

Answer 1

The ID of the control will differ, try to use $("[id$='Lookup']") to get an element ending with "Lookup".

Then you can use .val() to get the selected value of the dropdown: var id= $("[id$='Lookup']").val();

Answer 2

That's correct as suggested by Robert. But just in case, if there are more than one look up columns add an extra filter as shown in the below script

<script type="text/javascript">
    $(document).ready(function () {
        if ($("[id$='_Lookup'][title='<<FieldName>>']").length > 0) {
            $("[id$='_Lookup'][title='<<FieldName>>']").change(function () {
                alert($("[id$='_Lookup'][title='<<FieldName>>']").val());
            });
        }
    });
</script>

Replace <<FieldName>> with your Field Title.