function validEmail (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
            }
}  // for (i=o.. 

        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
    }  // validEmail