var expMenu=false;

function showMenu(menuid) {
  var el=document.getElementById(menuid);
  el.style.visibility="visible";
  el.style.position="static";
  expMenu=true;
}

function hideMenu(menuid) {
  var el=document.getElementById(menuid);
  el.style.visibility="hidden";
  el.style.position="absolute";
  expMenu=false;
}

function changeExp() {
  if(expMenu==true) {
    hideMenu("expeditions");
  } else {
    showMenu("expeditions");
  }
}