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[whatwg] Make "foo@bar.com, " a valid email address list

From: Alex Bishop <alexbishop@gmail.com>
Date: Sun, 24 Oct 2010 18:05:26 +0100
Message-ID: <4CC46756.2060204@gmail.com>
On 23/10/2010 22:16, Garrett Smith wrote:
> On 10/22/10, Anne van Kesteren <annevk at opera.com>  wrote:
>> On Fri, 22 Oct 2010 19:44:42 +0200, Boris Zbarsky <bzbarsky at mit.edu>  wrote:
>>> On 10/22/10 1:25 PM, Garrett Smith wrote:
>>>> What is wrong with splitting on comma, e.g.
>>>>
>>>> var validAddressList = inp.value.split(",");
>>>
>>> That depends on what meaning of "email address" is used here.  Is:
>>>
>>>     "Zbarsky, Boris" <bzbarsky at mit.edu>
>>>
>>> a valid "email address"?
>>
>> Not per HTML5.
>>
>
> Link:
> http://www.w3.org/TR/2010/WD-html-markup-20101019/input.email.html
>
> Quote:
>      A single e-mail address.
>      Any string that matches the following [ABNF] production:
>
>      1*( atext / "." ) "@" ldh-str 1*( "." ldh-str )
>
>      ?where atext is as defined in [RFC 5322], and ldh-str is as
> defined in [RFC 1034].

Definition of atext from RFC 5322:

>    atext           =   ALPHA / DIGIT /    ; Printable US-ASCII
>                        "!" / "#" /        ;  characters not including
>                        "$" / "%" /        ;  specials.  Used for atoms.
>                        "&" / "'" /
>                        "*" / "+" /
>                        "-" / "/" /
>                        "=" / "?" /
>                        "^" / "_" /
>                        "`" / "{" /
>                        "|" / "}" /
>                        "~"

ALPHA and DIGIT are themselves defined in RFC 5234 to be the letters A 
to Z (upper-case or lower-case) and the digits 0 to 9 respectively.

Definition of ldh-str from RFC 1034:

> <ldh-str> ::= <let-dig-hyp> | <let-dig-hyp> <ldh-str>
>
> <let-dig-hyp> ::= <let-dig> | "-"
>
> <let-dig> ::= <letter> | <digit>
>
> <letter> ::= any one of the 52 alphabetic characters A through Z in
> upper case and a through z in lower case
>
> <digit> ::= any one of the ten digits 0 through 9

In other words, the letters A to Z (upper-case or lower-case), the 
digits 0 to 9 and the hyphen.

Therefore

     "Zbarsky, Boris" <bzbarsky at mit.edu>

is not a valid email address because the portion before the @ contains 
characters that are not atext (namely, the quotation marks, the comma, 
the spaces and the left angle bracket) or dots, and the portion after 
the @ contains characters that are not ldh-str or dots (namely, the 
right angle bracket).

bzbarsky at mit.edu is, however, a valid email address.

Alex

-- 
Alex Bishop
alexbishop at gmail.com
Received on Sunday, 24 October 2010 10:05:26 UTC

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