vorigeid = "";

function show(id, id2)
{
  if (vorigeid != "") { document.getElementById(vorigeid).style.display = "none"; }
  vorigeid = id;
  id2 = 'intro';
  document.getElementById(id).style.display = "block";
  document.getElementById(id2).style.display = "none";
}

function sluiten(id)
{
document.getElementById(id).style.display = "none";
}

function showe(div)
{
        var thisLevel = document.getElementById(div);
     

        if (thisLevel.style.display == "none")
        {
                thisLevel.style.display = "block";
               
        }
        else
        {
                var thisLevel = document.getElementById(div);
                thisLevel.style.display = "none";
               
        }
}