function isValidEmail() {
  var email = document.forms.newsletter_form.email.value;
  var AtPos = email.indexOf("@");
  var StopPos = email.lastIndexOf(".");
  if (email == "") return 0;
  if (AtPos == -1 || StopPos == -1) return 0;
  if (StopPos < AtPos) return 0;
  if (StopPos - AtPos == 1) return 0;
  return 1;
}

function checkForm(action) {
// Checks 'newsletter_form' for valid 'email' and entered 'name'
  if (document.forms.newsletter_form.name.value) {
    if (isValidEmail()) {
      showHTML('alert', 'Thank You - Processing Your Request...');
      var query_str = '?email=' + document.forms.newsletter_form.email.value + '&name=' +  document.forms.newsletter_form.name.value + '&action=' + action;
      window.location = "http://www.natashamostert.com/newsletter/send_mail.php" + query_str;
    }
    else { 
      setDisplay('alert', 'block');
      showHTML('alert', 'Please Enter A Valid E-mail Address');
      return;
    }
  }
  else {
    setDisplay('alert', 'block');
    showHTML('alert', 'Please Enter Your Name');
    return;
  }
}