function isMailAddress(m) {
   if ((m == '') || (m == ' ')) { return false; }

    var a = 1;
    var ml = m.length;

    while ((ml>a) && (m.charAt(a) != "@")) { a++ }
    if ((a >= ml) || (m.charAt(a) != "@")) {
	return false;
    } else {
	a = a + 2;
    }
    while ((ml > a) && (m.charAt(a) != ".")) { a++ }
    if ((a >= ml - 1) || (m.charAt(a) != ".")) {
	return false;
    } else {
    return true;
    }
}

function validate_tellafriend (obj) {
	var valid = true;
	msg = "";
	
	if (obj.yourname.value == "") {
		msg += "Please enter your name.\n";
		valid = false;
		obj.yourname.focus();
	}

	if (!isMailAddress(obj.youremail.value)) {
		msg += "Please enter a valid email address for yourself.\n";
		valid = false;
		obj.youremail.focus();
	}

	if (!isMailAddress(obj.email.value)) {
		msg += "Please enter a valid email address for your friend.\n";
		valid = false;
		obj.email.focus();
	}
	
	if (!valid)	alert(msg);

	return valid;
}