HTML mail [was Re: FEL was Re: Hi]

[Tim]

On Mon, 2010-08-09 at 03:27 +0100, Marko Vojinovic wrote:
> Aaahhh, well, so you are saying that an e-mail can contain both plain
> text version and html version of the same message simultaneously?

Yes, that's the main use of multipart/alternative.  It means that the
message has multiple parts, and that some parts are alternatives for
each other (e.g. plain text or HTML, though it could be other rendering
techniques, too).  Generally, it's in referral to the message.  Though,
theoretically, you could have multipart alternatives for other portions
of message content (e.g. show an attached TIFF or JPEG file).

In some cases, the plain text part may just be a wimp out message saying
"your mail client cannot display the contents of this message, upgrade
it."  Which, strictly speaking is a non-compliant message, as the plain
text wimp out message is not an alternative rendering of the HTML
version.

Quite a few sending clients will put such a pre-amble before both
sections.  So that a compliant client will show you the plain text or
the HTML version, and clients that can't handle MIME multiparts will
show a warning preamble (this message is a multipart...) before all of
the content.

Spam often contains bogus crap in the plain text part, and the spam in
the HTML alternative.  Some anti-spam systems will assess the content of
both sections, and flag such badly mismatched content is being very
highly likely to be spam.

Clients that can handle multiparts usually let you pick your preferred
default.  It'd be quite crap of such clients not to give you a choice.

-- 
[tim at localhost ~]$ uname -r
2.6.27.25-78.2.56.fc9.i686

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