function add_toggle(elem){
   var target = elem.id+'_cont';
   Effect.BlindUp(target,{duration: 1.0});
   var func = function(){
    Effect.toggle(target,'blind',{duration: 0.2});
   };
   Event.observe(elem,'click',func);
 }
 function init(){
   var menu = $('menu_list');
   var list = menu.getElementsByTagName('dt');
   for(var i = 0;i<list.length; i++){
      add_toggle(list[i]);
   }
}
Event.observe(window,'load',init);