Links and Webs - HTML and XHTML: The Definitive Guide - page 306

hexadecimal equivalent, %20 , because many email programs won't make
the proper substitution. It's best to use spaces because the email pro-
grams that don't honor the spaces simply truncate the parameter to the
first word.
The second URL places the address [e-mail] in the cc field
of the message. Similarly, the last example sets the bcc field. You may
also set several fields in one URL by separating the field definitions with
ampersands. For example, this URL sets the subject and cc addresses:
mailto:[e-mail]?subject=Loved your book!&cc=[e-mail]&bcc
=[e-mail]
Not all email programs accept or recognize the bcc and cc extensions in
the mailto URLsome either ignore them or append them to a preceding
subject. Thus, when forming a mailto URL, it's best to order the extra
fields as subject first, followed by cc and bcc. And don't depend on the
cc and bcc recipients being included in the email.
6.2.6. The ftp URL
The ftp URL is used to retrieve documents from a File Transfer Protocol
(FTP) server. [*] It has the format:
[*] FTP is an ancient Internet protocol that dates back to the Dark Ages, around 1975. It was designed
as a simple way to move files among machines and is popular and useful to this day. Many HTML/
XHTML authors use FTP to place files on their web servers.
ftp:// user : password @ server : port / path ; type = typecode