В HTML-верх:
Код:

Код:
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js"></script>

В HTML-низ:
Код:

Код:
<style>
#button-spoiler {background-image:url('https://forumupload.ru/uploads/0000/12/13/488-1.gif'); padding:0; line-height:0; background-position:center; background-repeat:no-repeat; height:26px; width:100%}
</style>
<script type="text/javascript">
function tag_spolier()
{var FoundErrors = '';
var enterTITLE = prompt("Введите описание спойлера", 'Спойлер');
bbcode('[spoiler]',('|'+enterTITLE+'[/spoiler]'));}
if(form=document.getElementById("form-buttons"))
form.getElementsByTagName("tr")[0].insertCell(19).innerHTML="<img src='/i/blank.gif' title='Вставить спойлер' id='button-spoiler' onclick=\"tag_spolier()\">"
function addSpoilerSpoiler(str,from,internal){
var pos=0,pos2=0,newpos=0
if((pos=str.indexOf("[spoiler]",from))==-1) return str;
if((pos2=str.indexOf("[/spoiler]"),pos+9)==-1) return str;
newpos=str.indexOf("[spoiler]",pos+9)
if(newpos<pos2 && newpos!=-1) str=addSpoiler(str,pos+9,true)
if((pos2=str.indexOf("[/spoiler]",pos+9))==-1) return str;

txt = str.substring(pos+9,pos2);
if((sepPos=txt.indexOf("|",0))==-1) return str;

str=str.substring(0,pos)+makeSpoilerSpoiler(txt.substring(0,sepPos),txt.substring(sepPos+1,txt.length))+str.substring(pos2+10,str.length)

if( str.indexOf("[spoiler]")!=-1 && internal==false) str=addSpoilerSpoiler(str,0,false)
return str}

function makeSpoilerSpoiler(txt1,txt2){
txt='<div class="quote-box" style="padding:1px;background: none;border: 0;"><cite style="width:100%;margin:0;"><input class="spoiler-button" style="width:140px;font-size:10px; margin:0; cursor: pointer" type="button" value="'+txt2+'"></cite><blockquote class="quote-box" style="display:none; width: 80%;border: 1px solid black;margin:0;">'+txt1+'</blockquote></div>'
return txt}

$(document).ready(function(){
     $("div.quote-box > cite > input.spoiler-button").click(function(){
$(this).parents("div.quote-box").find("blockquote.quote-box").toggle("normal");
     });
});


if((document.URL.indexOf("viewtopic.php")!=-1) || (document.URL.indexOf("post.php")!=-1)){
elm=document.getElementById("pun-main").getElementsByTagName("div")
for(x in elm) if(elm[x].className=="post-content"){
var post=elm[x]
post.innerHTML=addSpoilerSpoiler(post.innerHTML,0,false)}}