function isAlphaNum(stringToTest)
{
	var validAlphaNum = /^[a-zA-Z0-9]+$/;
	var isValid;

	isValid = false;
	if (validAlphaNum.test(stringToTest))
	{
		isValid = true;
	}

	return isValid;
}

function isValidEmailAddress(stringToTest)
{
	var validEmailAddress = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	var isValid;

	isValid = false;
	if (validEmailAddress.test(stringToTest))
	{
		isValid = true;
	}

	return isValid;
}