[TosaInu]

We have a spoiler code and I modified that one to make collapsable quotes. Nesting and Cache proof.

Same template bbcode_quote, replace the whole content:

<div style="margin:5px 20px 20px 20px">

<div class="smallfont" style="margin-bottom:2px">

<input type="button" value="Show" style="width:45px;font-size:10px;margin:0px;padding:0px;" onclick="if (this.parentNode.parentNode.getElementsByTagName('div')[1].getElementsByTagName('div')[0].style.display != '') { this.parentNode.parentNode.getElementsByTagName('div')[1].getElementsByTagName('div')[0].style.display = '';this.innerText = ''; this.value = 'Hide'; } else { this.parentNode.parentNode.getElementsByTagName('div')[1].getElementsByTagName('div')[0].style.display = 'none'; this.innerText = ''; this.value = 'Show'; }">

<if condition="$show['username']">
	<phrase 1="$username">$vbphrase[originally_posted_by_x]</phrase>: click show to read.
     <else />
         Quote: click show to read.
     </if> 

</div>

<div class="alt2" style="margin: 0px; padding: 6px; border: 1px inset;">

<div style="display: none;">

	<class="alt2" style="border:1px inset">
		<if condition="$show['username']">				           <div style="font-style:italic">$message</div>
		<else />
		    $message
		</if>

</div>

</div>

</div>

Thanks to Hellcat.