<script type="text/javascript">
var base_url = "<?php echo base_url();?>";

    $(document).ready(function() {
        $('select[name="make"]').on('change', function() {
            var makeid = $(this).val();
            if(makeid) {
                $.ajax({
                    url: base_url + 'myform/ajax/'+makeid,
                    type: "GET",
                    dataType: "json",
                    success:function(data) {
                        $('select[name="model"]').empty();
                        $.each(data, function(key, value) {
                            $('select[name="model"]').append('<option value="'+ value.id +'">'+ 'salam' +'</option>');
                        });
                    }
                });
            }else{
                $('select[name="model"]').empty();
            }
        });
    });
</script>