Alternance entre divs

function getcom(id, i) {
if(!isnan(id)) document.getelementbyid('c' + id).style.height = '0px';
else  { 
	var reg = /c/;
	var str = id;
	var newid = str.split(reg);
	document.getelementbyid(parseint(newid[1]), 10).style.height = '0px';
}
	var ob = document.getelementbyid(id);
	i += 4;
				
	ob.style.height = i + "px";
				
	if (ob.offsetheight < ob.scrollheight) {
	settimeout(function() {
	getcom(id, i);
	}, 10);
}
}
			
function hidecom(id, i) {
	var ob;
	if(i < document.getelementbyid('c' + id).style.height)
		ob = document.getelementbyid('c' + id);
	else
		ob = document.getelementbyid(id);
	i -= 4;
				
					
	ob.style.height = i + "px";
							
	if (i > 0) {
		settimeout(function() {
			hidecom(id, i);
		}, 10);
	}
}

<h4 id="h0">

	<span style="float:left;" onclick="getelementbyid('h0').style.backgroundimage='url(images/comment.png)';">
		<a href="javascript:hidecom('0', parseint(document.getelementbyid('0').style.height, 10));">
			cacher
		</a>
	</span>
	<span onclick="getelementbyid('h0').style.backgroundimage='url(images/commenth.png)';">
		<a href="javascript:getcom('c0', 0);">
			ajouter un commentaire
		</a>
		 - 
		<a href="javascript:getcom('0', 0);">

			pas de commentaire
		</a>
	</span>
</h4>

<div id="0" class="comment">
<p>trucs</p>
</div>
				
<div id="c0" class="comment">
	<p>
		<textarea></textarea>
	</p>
</div>