<script src="https://smtpjs.com/v3/smtp.js">
</script>
Email.send({
Host : "smtp.yourisp.com",
Username : "username",
Password : "password",
To : 'them@website.com',
From : "you@isp.com",
Subject : "This is the subject",
Body : "And this is the body"
}).then(
message => alert(message)
);