Star rating script code example.

star-rating.js

    $(function() {
        $('.driver-rating').barrating({
            theme: 'fontawesome-stars',
            initialRating: "<?php echo $averageRating; ?>",
            showSelectedRating: true,
            // onSelect is what triggers the saving of the rating.
            onSelect: function(value, text, event) {

                // Get element id by data-id attribute
                var el = this;
                var el_id = el.$elem.data('id');

                // rating was selected by a user
                if (typeof(event) !== 'undefined') {

                    var split_id = el_id.split("_");
                    var postid = split_id[1]; // postid.

                    alert(postid + ' ' + value);

                    // AJAX Request
                    $.ajax({
                        url: "<?php echo $ajax_url; ?>",
                        type: 'post',
                        action: 'my_function_name',
                        data: {postid:postid,rating:value},
                        dataType: 'json',
                        success: function(data) {
                            // Update rating.
                            var therating = data['rating'];
                            $('#avgrating_'+postid).text(therating);
                        }
                    });
                }
            } // end onSelect
        });
    });