function treeMenu(id) {
 var disp = document.getElementById(id).style.display;

 if(disp != "none" || disp == "") {
   document.getElementById(id).style.display = "none";
  }
 else {
   document.getElementById(id).style.display = "block";
  }
}

function openTree(id){
   document.getElementById(id).style.background = "yellow";
}