This is ... a bone of contention; basically, the email address is perfectly valid - but the browsers can't agree on what the correct encoding is - whether it is [email protected] vs %-encoding, and no single encoding works on all browsers. We've gone with the former for now, as it has wider compatibility - BUT I was very disappointed that when google added an official mailto: handler, they broke this (so it comes in as foo [email protected]), when every other browser works the other way. FWIW, the previous unofficial handlers in gmail were also broken.
This is discussed more https://webmasters.stackexchange.com/questions/15920/should-plus-be-encoded-in-mailto-hyperlinks, and AFAIK the conclusion is: it is ambiguous spec.
But! Try it in IE/FF/Safari/Chrome etc to see it work/not-work. You might need to test both the "mailto:" handler (i.e. going to an email client), and the "copy email address" that most browsers will add as a context menu. Sigh.
Example: http://jsfiddle.net/zmEPe/
Browser | With + | With %2b
| Click link | Copy address | Click link | Copy address
------------+---------------+--------------|---------------|----------------
Chrome 18 | Fail (" ") | Pass ("+") | Pass ("+") | Fail ("%2b")
w/ GMail | | | |
| | | |
IE 9 | Pass ("+") | N/A | Pass ("+") | N/A
w/LiveMail | | | |
| | | |
Safari 5 | Pass ("+") | Pass ("+") | Pass ("+") | Fail ("%2b")
w/ LiveMail | | | |
| | | |
Firefox 10 | Pass ("+") | Pass ("+") | Pass ("+") | Pass ("+")
w/ LiveMail | | | |
So: if we want this to work everywhere, we're going to need per-browser markup, which is - just wrong.
From the table, and the spec, I conclude that mailto:[email protected] is the more right representation, and if only the GMail handler wasn't broken, the world would make sense everywhere.
Blame GMail.
I tested this and logged a bug as soon as the official GMail mailto handler was released. AFAIK, it disappeared into the ether.
