UI Page get value from g:ui_reference and pass to script include

Hi guys,

I have two reference fields on a UI Page. I would like the second reference field to display values depending on what's selected on the first reference field and pass this value to a script include. Would you know how to achieve this? My code javascript:busServiceBulkUpdateQuery($('channel').value)does not work.. goranlundqvist any ideas?

 <div class="form-group">
   <label class="reference-label">${gs.getMessage('Channel')}</label>
   <g:ui_reference class="col-xs-12" name="channel" table="u_cmdb_ci_service_channel" query="u_active=true" />
   </div>
   <div class="form-group">
   <label class="reference-label">${gs.getMessage('Business Service')}</label>
   <g:ui_reference name="bus_svc" table="u_cmdb_ci_service_business" query="javascript:busServiceBulkUpdateQuery($('channel').value)" />
   </div>