lement contents to pre-enhanced version
            document.head.innerHTML = initialHead;
            document.body.innerHTML = initialBody;
            
            // create enhanced version link
            var el = document.createElement("a");
            el.id = "toggle_enhanced";
            el.setAttribute("href", "");
            el.innerHTML = "Enhanced version";
            var back = function(e) {
                 e.preventDefault();
                 window.history.back();
            }
        