Mine

<form action="" method="post">    <a id="simple" href="#" onclick="showSimple()">Simple</a>    <p>Some description... example</p>    <a id="advanced" href="#" onclick="hideAdvanced()">Advanced</a>    <p>Some description... example</p>    <div id="simpleDIV">	<div id="field" class="fld" style="height:25px">	    <label>Look & Feel:</label>	    <!--<input type="text" id="urlreturn" name="urlreturn" value="http://www." size="35" />-->	</div>    </div>    <div id="advancedDIV">	<div id="field" class="fld" style="height:25px">	    <label>Look & Feel:</label>	    <input type="text" id="urlreturn" name="urlreturn" value="http://www." size="35" />	</div>    </div>    <div class="fld">	<label>&nbsp; </label>	<input id="submit" type="submit" value="Go!" />    </div></form><script type="text/javascript">    // <![CDATA[		$('simpleDIV').hide();	$('advancedDIV').hide();		var visible = null;		function showSimple() {	    	    if(visible == 'advanced') {				hideAdvanced();	    }	    	    new Effect.SlideDown('simple');	    	    visible = 'simple';	}		function hideSimple() {	    new Effect.SlideUp('simple');	}		function showAdvanced() {	    	    if(visible == 'simple') {				hideSimple();			    }	    	    new Effect.SlideDown('advanced');	    	    visible = 'advanced';	}		function hideAdvanced() {	    new Effect.SlideUp('advanced');	}	    // ]]></script>