MyBB

Regular Expression:
\[spoiler=(.*?)\](.*?)\[/spoiler\]

Replacement:
<tag><div style="margin:20px; margin-top:5px">
<div class="smallfont" style="margin-bottom:2px"><b>Spoiler</b>: $1 <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'; }">
</div>
<div class="alt2" style="margin: 0px; padding: 6px; border: 1px inset;">
<div style="display: none;">
$2
</div>
</div>
</div>
</tag>

Just do something like this:

[spoiler=Information from the new CoroCoro Magazine]
Information Here
[/spoiler]

CoroCoro

This is neat, thanks!

Cool. Thank you (:

Testing....

doesn't work :/, if someone could fix it. it would be awesome!

It works for me. Are you sure you pasted the right code?

my fault, used the code wrong to post with.

Could you add some screenshot/preview? Thanks.

Works...

Very nice code :D