function Validator(theForm)
{

  if (theForm.Name.value == "")
  {
    alert("Please enter a value for the \"Your name\" field.");
    theForm.Name.focus();
    return (false);
  }

  if (theForm.Telephone.value == "")
  {
    alert("Please enter a value for the \"Your telephone number\" field.");
    theForm.Telephone.focus();
    return (false);
  }

  if (theForm.PostalAddress.value == "")
  {
    alert("Please enter a value for the \"Your postal address\" field.");
    theForm.PostalAddress.focus();
    return (false);
  }

  if (theForm.EventDate.value == "")
  {
    alert("Please enter a value for the \"Date of event\" field.");
    theForm.EventDate.focus();
    return (false);
  }

  if (theForm.CrowdSize.value == "")
  {
    alert("Please enter a value for the \"Expected crowd size\" field.");
    theForm.CrowdSize.focus();
    return (false);
  }
  return (true);
}