RecorteX

Si quieres implementar algo rapido de moo.fx, sugiero lean la documentacion para poder dominar el script.

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<script type="text/javascript" src="/moo.fx/prototype.lite.js"></script>
<script type="text/javascript" src="/moo.fx/moo.fx.js"></script>
<script type="text/javascript" src="/moo.fx/moo.fx.pack.js"></script>
<script type="text/javascript">
	function init(){
		var toggles = document.getElementsByClassName('head_acordion');
                var stretchers = document.getElementsByClassName('body_acordion');
		var myAccordion = new fx.Accordion(toggles, stretchers);
	}
</script>
<div>
  <div>
    <div>
      <div class="head_acordion"><a href="javascript:;">titulo</a></div>
      <div class="body_acordion">
        <p>contenido</p>
      </div>
      <div class="head_acordion"><a href="javascript:;">titulo</a></div>
      <div class="body_acordion">
        <p>contenido</p>
      </div>
    </div>
  </div>
</div>
<script type="text/javascript">
		init();				
</script>
 

Ahora si quieren que el primer panel se abre predeterminadamente hay que agregar este codigo

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function checkHash(){
			var found = false;
			toggles.each(function(h3, i){
				if (window.location.href.indexOf(h3.title) > 0) {
					myAccordion.showThisHideOpen(stretchers[i]);
					found = true;
				}
			});
			return found;
		}
		
		if (!checkHash()) myAccordion.showThisHideOpen(stretchers[0]);
 

Para que quede al final asi:

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<script type="text/javascript" src="/moo.fx/prototype.lite.js"></script>
<script type="text/javascript" src="/moo.fx/moo.fx.js"></script>
<script type="text/javascript" src="/moo.fx/moo.fx.pack.js"></script>
<script type="text/javascript">
	function init(){
		var toggles = document.getElementsByClassName('head_acordion');
                var stretchers = document.getElementsByClassName('body_acordion');
		var myAccordion = new fx.Accordion(toggles, stretchers);
                function checkHash(){
			var found = false;
			toggles.each(function(h3, i){
				if (window.location.href.indexOf(h3.title) > 0) {
					myAccordion.showThisHideOpen(stretchers[i]);
					found = true;
				}
			});
			return found;
		}
		
		if (!checkHash()) myAccordion.showThisHideOpen(stretchers[0]);
	}
</script>
<div>
  <div>
    <div>
      <div class="head_acordion"><a href="javascript:;">titulo</a></div>
      <div class="body_acordion">
        <p>contenido</p>
      </div>
      <div class="head_acordion"><a href="javascript:;">titulo</a></div>
      <div class="body_acordion">
        <p>contenido</p>
      </div>
    </div>
  </div>
</div>
<script type="text/javascript">
		init();				
</script>