html:
<ul id="target">
<li>1</li>
<li>2</li>
<li>3</li>
<li>4</li>
</ul>
js:
var dom = document.getElementById('target');
var list = dom.getElementsByTagName('li');
var html='';
for (var i=list.length-1;i>=0;i--){
html = html + '<li>'+list[i].innerHTML+'</li>';
}
dom.innerHTML = html;