var head="display:''"

function change(){
   if(!document.all)
      return
   if (event.srcElement.id=="foldheader") {
      var srcIndex = event.srcElement.sourceIndex
      var nested = document.all[srcIndex+1]
      if (nested.style.display=="none") {
         nested.style.display=''
         event.srcElement.style.listStyleImage="url()"
      }
      else {
         nested.style.display="none"
         event.srcElement.style.listStyleImage="url()"
      }
   }
}

document.onclick=change