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