(function __init__(){
    if(typeof document.body != 'undefined'){
        document.body.onload = function(){
            var wMenubar = document.getElementById("wMenuBar"),
                wLogo = document.getElementById("wLogo");
            window.onscroll = function (e){
                if(window.scrollY > 50){
                    wMenubar.className="small";
                    wLogo.src = "logo-small.png";
                }else{
                    wMenubar.className="big";
                    wLogo.src = "logo.png";
                }
            }
        };
    }else{
        setTimeout(__init__,10);
    }
})();