<div><div style="margin: 5px;">
<div class="smallfont" style="margin-bottom:
2px;"><i><span style="font-weight:
bold;">Spoiler for : BlaBlaBla...</span></i><input
value="Show" style="margin: 0px; padding: 0px;
width: 60px; font-size: 10px;" 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'; }" type="button"/>
</div>
<div class="alt2" style="border: 1px inset ; margin:
0px; padding: 6px;">
<div style="display: none;">
isi spoiler...</div></div></div></div>

4. Ganti tulisan isi spoiler... dengan tulisanmu sendiri

5. Mudah bukan..??