function clickclear(thisfield, defaulttext) {
  if (thisfield.value == defaulttext) {
    thisfield.value = "";
  }
}

function clickrecall(thisfield, defaulttext) {
  if (thisfield.value == '') {
    thisfield.value = defaulttext;
  }
}

function setURI() {
  classid = document.getElementById("classid").value;
  document.getElementById("uri").value = "/eclass/classroom.php?id=" + classid; 
}

function checkClass(){
  classid = document.getElementById("classid").value;
  if (classid == ''){
    alert("Please select a class");
    return false;
  }
  return true;
}