The short answer is that you can't do it using JavaScript alone. You'd need a server-side handler to connect with the SMTP server to actually send the mail. There are many simple mail scripts online, such as this one for PHP:
Simple PHP mail script
Using a script like that, you'd POST the contents of your web form to the script, using a function like this:
jQuery.post
And then the script would take those values, plus a username and password for the mail server, and connect to the server to send the mail.
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