To sum up: Mailto is the recipient address, cc is the cc address, bcc is the bcc address, subject is the subject of the email, and body is the body of the email, if there are multiple parameters after Mailto, the first parameter must start with "?" Start.
The following is a complete example:
Mailto: aaa@xxx.com? Cc = bbb@yyy.com & bcc = ccc@zzz.com & subject = subject & body = Email content
The email address on the webpage is often searched by some automatic search programs such as "mail-robot", so that others may use the searched email address to send spam to you, in order to reject these spam emails, we can write the public email addresses on the webpage in ASCII code and replace each letter or number with ASCII code, add "& #" before each ASCII code. In this way, the automatic search program will not be able to find our email addresses, so all kinds of Spam with unknown origins will be greatly reduced.