<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>