make server side jquery searching using jquery.select2.js

Question

how to use severside side search in drop dowm my code is here

the data in drop down come from database .... any help please ...

$(document).ready(function() {

            $(".js-example-basic-single").select2({

                ajax: {
                    url: "<?php echo base_url();?>index.php/site/getdatabyajax2",
                    dataType: 'json',
                    delay: 250
                }
            })

        });

    </script>
    <h4 class="label">Filter Data By Name </h4>
    <select class="js-example-basic-single" id="nme" name="name">

        <?php foreach($groups1 as $name){ ?>
            <option value="<?php echo $name->emp_id; ?>"><?php echo $name->Name; ?></option>;
        <?php } ?>
    </select>