How to find out where a JQuery function is actually defined.

Suppose  I have a JQuery date picker control. Below is the JQuery I use to display the date picker calendar. Using my web browser Either IE 11, or Chrome or FireFox , how can I find out where the function datepicker actually exists?  I have several script tags that reference jquery files, however I have no idea where the function datepicker is defined. Is there a way to find this out when the browser displays by datepicker? Is there way to find out where date picker is defined? Meaning which directory it is defined in?



 <script type="text/javascript">
        $(function () {
            $("[id$=txtContactDate]").datepicker({
                changeMonth: true,
                changeYear: true
            });
        });
    </script>