in my code also the choice values are not hardcoded, its coming from db only...here is the full code

<g:evaluate jelly="true" object="true">

        var GR = new GlideAggregate("<table name>");

        GR.addQuery("<field name>", '${sysparm_sysID}');

        GR.groupBy("<field name>");

        GR.query();

      </g:evaluate>

<tr align="center">

<td id="description" align="right" >Select Approval Name:</td>

<td id="approvers" >

<select id="abc" onchange="test()" style="width:200px">

<option value=''> -- None --   </option>

<j:while test="${GR.next()}">

    <option value = "${GR.<field 1>},${GR.<field 2>}" > ${GR.<display field>} </option>

</j:while>

  </select>

  </td>

        </tr>