<script type='text/javascript'>    
function Switchable(classname) {    
function getElementsByClassName(imgclass) {    
     if ( document.getElementsByClassName ) {    
      return document.getElementsByClassName(imgclass);    
     } else {    
      var nodes = document.getElementsByTagName('*'),    
      tmp = [];    
      for ( var i = 0; i < nodes.length; i++ ) {    
       if ( new RegExp('\\b' + imgclass + '\\b').test(nodes[i].className) ) {    
        tmp.push(nodes[i]);    
       }    
      }    
      return tmp;    
     }    
}    

function Next(element) {    
     var next = element;    
     while (next = next.nextSibling)    
      if ("innerHTML" in next)    
       return next;    
     return element;    
}    

function getCookie(a){var b=document.cookie.match(new RegExp("(?:^|; )"+a.replace(/([\.$?*|{}\(\)\[\]\\\/\+^])/g,"\\$1")+"=([^;]*)"));return b?decodeURIComponent(b[1]):undefined}function setCookie(b,f,c){c=c||{};var i=c.expires;if(typeof i=="number"&&i){var h=new Date();h.setTime(h.getTime()+i*1000);i=c.expires=h}if(i&&i.toUTCString){c.expires=i.toUTCString()}f=encodeURIComponent(f);var a=b+"="+f;for(var e in c){a+="; "+e;var g=c[e];if(g!==true){a+="="+g}}document.cookie=a}    
     var nodes = getElementsByClassName(classname);    
     for (var i = 0; i < nodes.length; i++) {    
      var toggler = document.createElement("A");    
      toggler.href = "javascript://";    
      toggler.id = "toggler" + i;    
      toggler.innerHTML = getCookie("toggler" + i) == "hide" ? "+" : "-";    
      toggler.onclick = function () {    
       Next(this.parentNode).style.display = getCookie(this.id) == "hide" ? "" : "none";    
       setCookie(this.id, getCookie(this.id) == "hide" ? "show" : "hide", {    
        expires: new Date("01 Jan 2020")    
       });    
       this.innerHTML = getCookie(this.id) == "hide" ? "+" : "-";    
      };    
      Next(nodes[i]).style.display = getCookie("toggler" + i) == "hide" ? "none" : "";    
      nodes[i].appendChild(toggler);    
     }    
}    

Switchable("header");    
</script>

<div class='header'>    
Заголовок    
</div>    
<div>    
Содержимое    
</div>