UJS example

<!-- before: -->

<a href="#" onclick="alert('Hello world!'); return false;">Click Here</a>

<!-- after: -->

<a href="#" id="myAlert" data-message="Hello from UJS">Click Here</a>

<script type="text/javascript">
  $(function() {                     // in jQuery, $() appends an onLoad handler to document
    $('#myAlert').click(function () {    // adds an onClick handler to #myAlert
      alert('Hello, world!'); return false;
      })
    // we could add other elements' event handlers here
  });
</script>