// Returns true if the email address looks valid.
function validEmail(email)
{
    invalidChars = " /:,;"

    if (email == "") {                      // cannot be empty
        return false
    }
    for (i=0; i<invalidChars.length; i++) { // does it contain any invalid characters?
        badChar = invalidChars.charAt(i)
        if (email.indexOf(badChar,0) > -1) {
            return false
        }
    }
    atPos = email.indexOf("@",1)            // there must be one "@" symbol
    if (atPos == -1) {
        return false
    }
    if (email.indexOf("@",atPos+1) != -1) { // and only one "@" symbol
        return false
    }
    periodPos = email.indexOf(".",atPos)
    if (periodPos == -1) {                  // and at least one "." after the "@"
        return false
    }
    if (periodPos+3 > email.length) {       // must be at least 2 characters after the "."
        return false
    }
    return true
}