рабочий пример: http://kachay.ucoz.org/load/27-1-0-185 
 ------------------------------------------------- 
 <a onclick=sorrta()>Sort_АЯ</a> | <a onclick=sorrtz()>Sort_ЯА</a><br> 
 <ul> 
 <li>Вася 
 <li>Петя 
 <li>Аня 
 <li>Юра 
 </ul>  <script> 
 var myar= new Array(); 
 var li1=document.getElementsByTagName('li'); 
 function sorrta() { 
 for(var li2=0;li2<li1.length;li2++) { 
 myar[li2]=li1[li2].innerHTML; 
 } 
 myar.sort(); 
 for(var li3=0;li3<myar.length;li3++) { 
 li1[li3].innerHTML=myar[li3]; 
 } 
 } 
 function sorrtz() { 
 for(var li2=0;li2<li1.length;li2++) { 
 myar[li2]=li1[li2].innerHTML; 
 } 
 myar.sort(); 
 myar.reverse(); 
 for(var li3=0;li3<myar.length;li3++) { 
 li1[li3].innerHTML=myar[li3]; 
 } 
 } 
 </script>