jquery expander plugin not working

jquery expander plugin not working

the jquery plugin is not working on all the tags as its supposed to be.
here is the code
  1. <script type="text/javascript">
    $(document).ready(function() {

      // simple example, using all default options
      $('.expand_hide').expander();
     
      // *** OR ***
     
      //override some default options
      $('div p').expander({
        slicePoint:       5,  // default is 100
        expandText:         '[...]', // default is 'read more...'
        collapseTimer:    5000, // re-collapses after 5 seconds; default is 0, so no re-collapsing
        userCollapseText: '[^]'  // default is '[collapse expanded text]'
      });
     
    });
    </script>

















here is the html code

  1.  <div id="err_msg">
          <p>
          asdasdasdasdasdasdaaaa<br/>
          </p>


  2. </div>
  1. <div id="footer">
  2.     <p>Designed by:blah blah
  3.         <br />Copyright 2011 Team7</p>
  4.     </div>

Now the expander function is working for the footer only and is not working for the snippet with id err_msg.

Please help