Does anyone know if when sending a html newsletter what kind of support the major email clients have for the subject= and body= parts of the mailto tag?
The behavior varies by both email client and source application. Here's a likely enough example from my own system, using pjp's link.
<a href="mailto:me@somewhere.com?subject=Hello%20People">Send Mail</a>
- Mailto link followed within Outlook client successfully fills subject
- Mailto link followed in IE successfully fills subject for Outlook client
- Mailto link followed in Firefox fails for same Outlook client (subject text remains part of "TO" field)
I tried the same link in HTML emails read by gmail and Yahoo web clients.
- Gmail correctly opens a new message with desired subject
- Yahoo pre-fills the subject, but truncates at the space ("Hello" only)
That much variation on just one computer makes embedded mailto tricky to use. I bet that's why many email newsletters provide a "View as a web page" link in the header.
I imagine they've got quite good support for it. BUT!! But mailto will be used to send and email FROM the client TO me@somewhere.com . Thats definitely not you sending out a newsletter.
You'll have to send emails from the server, potentially in a background process.
EDIT: Slight rethink. Are you talking about you using an admin section with a link with multiple TO addresses that will then open an email client to send out your newsletter? In which case, even though the major browsers probably do have decent support, you shouldn't rely on it out in the wild, since its not in the standard (I think), so they are not required to support it.
EDIT AGAIN:
rfc 2368 info in support of my previous edit
来源：https://stackoverflow.com/questions/1310714/mailto-subject-and-body-support-in-email-clients