function isEmail(email) {
	invalidChars = " /:,;"
	if (email == "") { return (false); }
	for (i=0; i < invalidChars.length; i++) {
		badChar = invalidChars.charAt(i)
		if (email.indexOf(badChar,0) != -1) { return (false);	}
	}
	atPos = email.indexOf("@", 1)
	if (atPos == -1) {return (false);}
	if (email.indexOf("@", atPos + 1) != -1) {return (false);}
	periodPos = email.indexOf(".", atPos)
	if (periodPos == -1) {	return (false);}
	if (periodPos + 3 > email.length) {return (false);}
	return (true);
}