Ajax request via javascript

Hello Rubies,
      Have you tried AJAX request via javascript? Lets see the eg.

<script type="text/javascript">

  // Ajax without update parameter:
  function ajax_request(id){
    window._token = '<%= form_authenticity_token %>';
    var url = '/controller/action';
    var pars = 'id=' + id + '&authenticity_token=' + window._token;
    var myAjax = new Ajax.Request(url, {method: 'post', parameters: pars, onFailure: showFailure(), onSuccess: showSuccess() });
  }

  // Ajax with update parameter:
  function ajax_update_request(id){
    window._token = '<%= form_authenticity_token %>';
    var url = '/controller/action';
    var pars = 'id=' + id + '&authenticity_token=' + window._token;
    var myAjax = new Ajax.Updater('update_div_id', url, {method: 'get', parameters: pars, onFailure: showFailure(), onSuccess: showSuccess()});
  }

  function showSuccess(){
  }

  function showFailure(){
  }

</script>