function moveMenu(num) {
 var x = document.getElementById("menu"+num);
 var y = document.getElementById("submenu"+num);
 var z = document.getElementById("arrow"+num);

 if(x.className == "on") {
  x.className = "off";
  } else {
  x.className = "on";
 }

 if(y.className == "on") {
  y.className = "off";
  } else {
  y.className = "on";
 }

 if(x.className == "on") {
  z.src = "/images/buttons/arrow_on.png";
  } else {
  z.src = "/images/buttons/arrow_off.png";
  }
 }