function userAction(s) {
	if (s == 'accept') {
	  document.getElementById("Submit").disabled = false;
	} else {
	  document.getElementById("Submit").disabled = 'disabled';
	}
}

function doSubmit() {
  var e=0; var found=0;
  var s = document.getElementById("email").value;
  found = s.indexOf ('@');
  if (found < 1 || s.length - found < 4)
    e |= 1;
  s = document.getElementById("name").value;
  if (1 > s.length) {	
    e |= 2;
  }
  s = document.getElementById("password");
  if (s.value.length < 1 ||
      s.value != document.getElementById("pw2").value)
    e |= 4;
  var result = false;
  var error_msg = null;
  switch (e) {
  case 1:
    error_msg = "Please enter a correct email address (e.g., name@domain.com, student@dept.university.edu, first.last@some.where.uk).";
    break;
  case 2:
    error_msg = "Please make sure the name field is not empty.";
    break;
  case 3:
    error_msg = "Please enter a correct email address and make sure the name field is not empty.";
    break;
  case 4:
    error_msg = "Please enter the same password twice.";
    break;
  case 5:
    error_msg = "Please enter a correct email address and the same password twice";
    break;
  case 6:
    error_msg = "Please enter a name and the same password twice.";
    break;
  case 7:
    error_msg = "Please fill all fields.";
    break;
  default:
    result = true;
    break;
  }
  if (error_msg != null)
    alert (error_msg);
  return result;
}

function setButtons() {
  if (!document.getElementById("accept").checked)
    document.getElementById("Submit").disabled = 'disabled';
}