function checkEmptiness (obj, name)
{
  if (obj.value.length == 0)
  {
    window.alert ("Please enter a value for " + name + ".");
    obj.focus ();
    return false;
  }
  return true;
}

function checkDigits (obj, name, numDigits, emptyAllowed)
{
  if (emptyAllowed && obj.value.length == 0)
  {
    return true;
  }
  var matchString;
  matchString = "";
  for (i = 0; i < numDigits; i++)
  {
    matchString += "[0-9]";
  }
  if (obj.value.match (matchString) == null)
  {
    window.alert (name + " must have exactly " + numDigits + " digits.");
    obj.focus ();
    return false;
  }

  return true;
}

function checkDigits (obj, name, emptyAllowed)
{
  if (emptyAllowed && obj.value.length == 0)
  {
    return true;
  }
  var matchString;
  matchString = "";
  numDigits = obj.value.length;
  for (i = 0; i < numDigits; i++)
  {
    matchString += "[0-9]";
  }
  if (obj.value.match (matchString) == null)
  {
    window.alert (name + " must be a number.");
    obj.focus ();
    return false;
  }

  return true;
}