// Validate the form fields when the form is submitted.

function validateForm()
  {
  var err = false;
  var msg = "";
  with (document.forms[0])
  {
    if (name.value == "")
      {
      msg += "Please enter your name.\n";
      err = true;
      }
    else
      {
      var namePattern = /^[a-z]+\.?,? +[a-z]+\.?(,? +[a-z]+\.?)?(,? +[a-z]+\.?)?(,? +[a-z]+\.?)? *$/i;
        if (!namePattern.test(name.value))
          {
          msg += "Please enter both your first and last names.\n";
          err = true;
          }
      }
    if (email.value != "")
      {
      var emailPattern = /^[\w_\-]+(\.[\w_\-]+)*@[a-z0-9\-]+(\.[a-z0-9\-]+)*\.([a-z]{2,4}|museum|travel)$/i;
      if (!emailPattern.test(email.value))
        {
        msg += "Your email address has an error.\n";
        err = true;
        }
      }
    if (info.value == "")
    {
      msg += "Please enter the announcement information.\n";
      err = true;
    }
  }
  if (err)
    {
    window.alert (msg);
    return false;
    }
  else
    return true;
  }

window.onload = function () {
  if (document.forms.length > 0) document.forms[0].onsubmit = validateForm; 
}