function revealNext(el) {
         var next=el.nextSibling;
         while(next.nodeType != 1) next=next.nextSibling;
         next.style.display=((next.style.display=="none") ? "block" : "none");
        }

        function revealNextByTagName(tname) {
         var tag="reveal";
         var reveals=document.getElementsByTagName(tname);
         for (i=0; i<reveals.length; i++) {
         reveals[i].className+=" "+tag;
         reveals[i].onclick=function() {revealNext(this)}
         revealNext(reveals[i]);
         }
        }