/* toggleElement() */
function toggleElement(id)
{
  var element = document.getElementById("element" + id);
  var node    = document.getElementById("node" + id);

//flip value of element.sytle.display between none and block
  if(element.style.display == "none") {

    element.style.display = "block";
    
  }

  else {

    element.style.display = "none";
    
  }
}