how to call jquery function

<script type="text/javascript">
  //<![CDATA[

  function addfunction(){
   
    $('roles').addClassName('test');
   
  }
   function remofunction(){
   
    $('roles').removeClassName('test');
   
  }

   //]]>
  </script>

<%= link_to_remote( department.department_name,:url =>{ :action => :designation_list,:id => department.id },:html => { :class  => "deptRole" ,:loading => "addfunction();", :completed => "remofunction();" })%>

it calls the protype javascript function when loading ajax...
likewise how can i call the jquery function like above...
pls kindly help me out