HTML is not capable of sending mail or any other "active" behaviors. All you can do is to use an anchor, but
it does not send e-mail, it just
helps the user to start the default mail client capable of sending mail, and to fill in some of the data.
The URI
scheme is "mailto"; it is explained here with examples:
http://en.wikipedia.org/wiki/Mailto.
As you can see, you can fill in some optional fields in the mail client: address, subject and body. That said, this functionality is very limited. Other techniques which really can send mail are based on server-side programming.
If you have to form this URI dynamically based on some data, you can calculate the URI string and set it to the DOM of your HTML using JavaScript. If you know JavaScript, it's way too trivial, if you don't, a Quick Answer hardly can be a good place to explain all about JavaScript and DOM manipulations. So, if your JavaScript knowledge is somewhere in the middle and you want to solve such problem, feel free to ask some more specific questions on your possible concerns.
Again, HTML does not send e-mail.
—SA