function verifyRequired(url) {
  if (document.joinform["name1"].value == "") {
	alert("Please enter your first name.");
	document.joinform["name1"].focus();
    return false;
  }
  if (document.joinform["email1"].value == "") {
    document.joinform["email1"].focus();
    alert("Please enter your email address.");
    return false;
  }
  if (document.joinform["email1"].value != "") {
  	var regexp = /[\w-]+@([\w-]+\.)+[\w-]+/;
	if (!(regexp.test(document.joinform["email1"].value))) { 
    	alert("Please enter a valid email address.");
		return false;
	}
  }
  var queryString = url + "?name=" + document.joinform["name1"].value + "&email=" + document.joinform["email1"].value;
  document.joinform["MailingThankyouURL"].value = queryString;
  document.forms['joinform'].submit();
}