bootstrap select example with json data

<select class="selectpicker" data-live-search="true">

</select>

function load_buku(){
    $.getJSON("<?php echo base_url('index.php/perpus/buku_get_data')?>", function(json){
        var row = '';
        row+="<option value=''>- Pilih -</option>";
        for (var i=0; i<json.length; i++){
            row+="<option value='" + json[i].id + "'>" + json[i].nama_buku + "</option>";
        }

      $(".selectpicker").empty();
      $(".selectpicker").append(row);
      $(".selectpicker").selectpicker('refresh');
    })
}

load_buku();