How to add this spoiler ? bbcode

[katie hunter]

This looks rather complicated, i don't think it is that complicated... but i will ask around more.

--------------- Added [DATE]1401846448[/DATE] at [TIME]1401846448[/TIME] ---------------

the code would be something similar to this but not exactly working the same way

<div style="margin: 0px;"> 
<div class="smallfont" style="margin-bottom: 2px;"> 
<strong>Spoiler!</strong> <input value="Show" style="margin: 0px; padding: 0px; width: 45px; font-size: 10px;" onclick="if(this.parentNode.parentNode.getElementsByTagName('div')[1].getElementsByTagName('div')[0].style.display != 'inline') 
{ this.parentNode.parentNode.getElementsByTagName('div')[1].getElementsByTagName('div')[0].style.display = 'inline'; this.innerText = ''; this.value = 'Hide'; } 
else 
{ this.parentNode.parentNode.getElementsByTagName('div')[1].getElementsByTagName('div')[0].style.display = 'none'; this.innerText = ''; this.value='Show'; }" type="button" />
</div> 
<div class="alt2" style="border: 0px inset; padding: 0px;"> 
<div class="spoiler" style="display: none;">{param}</div> 
</div> 
</div>