A mailto URL will send an email message to the address in the URL, for example ‘mailto:foo@bar.com’ would compose a message to ‘foo@bar.com’.
The function called whenever url needs to send mail. This should normally be left to default from mail-user-agent. See Mail-Composition Methods.
An ‘X-Url-From’ header field containing the URL of the document that contained the mailto URL is added if that URL is known.
RFC 2368 extends the definition of mailto URLs in RFC 1738. The form of a mailto URL is
‘mailto:mailbox[?header=contents[&header=contents]]’
where an arbitrary number of headers can be added. If the header is ‘body’, then contents is put in the body otherwise a header header field is created with contents as its contents. Note that the URL library does not consider any headers `dangerous' so you should check them before sending the message.
Email messages are defined in rfc822.