HTML email: Difference between revisions

Revision as of 17:05, 14 September 2006

Revision as of 17:09, 14 September 2006

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* A few recipients have [[e-mail client]]s that cannot display HTML. This may be mitigated by the inclusion of an automatically generated plain text version, which may be missing important formatting information (e.g. an equation may lose a superscript and take on an entirely new meaning).

* HTML e-mail is larger than plain text. Even if no special formatting is used, there will be the overhead from the tags used in a minimal HTML document, and if formatting is heavily used it may be much higher.

** Many email clients are configured to send a plain text version of a message along with the HTML version, to ensure that it can be read even by text-only clients, using the <code>[[MIME#Content-Type|Content-Type]]: [[MIME#Alternative|multipart/alternative]]</code>, as specified in RFC 1521.<ref>[http://www.freesoft.org/CIE/RFC/1521/18.htm RFC 1521 7.2.3. The Multipart/alternative subtype]</ref><ref>[http://www.codestone.ltd.uk/software/docs/csmail/tn1010-11-2.pdf TN1010-11-2: Multipart/Alternative – Gracefully handling HTML-phobic email clients.]</ref><ref>[http://www.wilsonweb.com/wmt5/html-email-multi.htm Sending HTML and Plain Text E-Mail Simultaneously]</ref> This further increases the size.
** Download speed was more of a concern in the 1990s, though, when most users were accessing email servers through slow [[modem]]s. On a modern connection, the difference in download time between plain text and mixed message mail, which can be a factor of three or more, is negligible, especially when compared to images, music files, or other common attachments.<ref>[http://momentum.insertdisc.com/archives/2004/09/17/html_email_still_evil_part_1.html HTML Email - Still Evil?]</ref>

** Additionally, the plain text section of a multi-part message can be retrieved by itself, using [[IMAP]]'s FETCH command.<ref>[http://dsv.su.se/jpalme/ietf/mhtml-discussion.html Do we really want to send web pages in e-mail?]</ref>

* Some senders may excessively rely upon large, colorful, or distracting fonts making all but the shortest messages more difficult to read.

* HTML allows for a link to have a different target than the link's text. This can be a security issue for users, who may be fooled into believing that a link points to the website of an authoritative source (such as a bank) and unintentionally [[phishing|revealing personal details to a scammer]].