HTML Tip #1: Subjects in Mailto Links

This tip is dedicated to all the W3C working groups that keep writing things like “you may send your comments to the W3C XSLT/XPath/XQuery mailing list, public-qt-comments@w3.org. It will be very helpful if you include the string [UPD] in the subject line of your comment, whether made in Bugzilla or in email” in their drafts. I’ve gotten tired of making the following suggestion to each and every working group, so let me publish it here publicly for all to see.

It is easy to code a mailto link such that the subject line you’d like correspondents to use appeard automatically in their mail client. That way they don’t have to waste time typing it, and you don’t get so many messages where the correspondent forgets to put the magic keyword in the subject line. Here’s how:

Simply add a query string with a Subject field and a value being the subject line you want to use For example, the link for comments on XQuery updates should be:

<a href= "mailto:public-qt-comments@w3.org?Subject=[UPD]"> public-qt-comments@w3.org </a>

Spaces and other characters that cannot appear in URLs can be percent escaped, just as in http URLs. For example,

<a href= "mailto:public-qt-comments@w3.org?Subject=[UPD]%20Replace%20Me"> public-qt-comments@w3.org </a>

You can use the same trick to include additional headers in the message. Just add another field with a different name. For example, this link CC’s one of the editors of the spec personally:

<a href= "mailto:public-qt-comments@w3.org?Subject=[UPD]&CC=chamberlin%40almaden.ibm.com"> public-qt-comments@w3.org </a>

There are some security issues when setting headers other than Subject, and some e-mail clients may only allow you to set the Subject. Thunderbird does respect both Subject and CC headers. In practice, Subject is the only header I’ve ever needed to set anyway.

This is all completely standards conformant, and is endorsed by the original RFC 2368 that defined the mailto scheme as well as the enhanced version now being developed to replace it.

I will not swear that this works in all e-mail clients. I know it works with Eudora and Thunderbird on the Mac, the only two clients I’ve used with any regularity since I started browsing the Web. I strongly suspect it works in most other clients; and even if it it doesn’t work in a few, it doesn’t harm them to include this. Make your life and your users’ lives simpler. Include subject headers in mailto links.

This entry was posted on Tuesday, May 9th, 2006 at 9:14 am and is filed under Web Development. You can follow any responses to this entry through the Atom feed. Both comments and pings are currently closed.