// JavaScript Document<script type="text/javascript">

var image_id; //declare helper variable

$(document).ready(function()
{
  
  //hide the all of the element with class msg_body
  $(".cas_msg_body").hide();

  //toggle the componenet with class msg_body
  $(".cas_msg_head").click(function() {	
	$(this).next(".cas_msg_body").slideToggle(300,
											   function(){
												var icon = ($(this).is(':hidden')) ? "plus" : "minus";	 
												$("#image"+image_id).attr("src","/images/icon-"+icon+".gif");
											   });
  });
  
});