function othername() {
  var input = document.getElementById("userInput").value;
}

function pass() {
  var password = document.getElementById("password").value;
  return password;
}

function sendEmail() {
  Email.send({
    Host: "smtp.gmail.com",
    Username: othername(),
    Password: pass(),
    To: 'person@gmail.com',
    From: othername(),
    Subject: "Sending Email using javascript",
    Body: "This email was sent with javascript :)",
  })
  .then(function(message) {
    alert("mail sent successfully")
  });
};

<script src="https://smtpjs.com/v3/smtp.js"></script>
<p style="position:absolute; top:50%; left:5%; width:40%;">Put in your email address:</p>
<p style="position:absolute; top:70%; left:5%; width:40%;">Put in your password(we do not save this, read more in our about page)</p>
<form id="form" onsubmit="return false;">
  <input style="position:absolute; top:60%; left:5%; width:40%;" type="text" id="userInput" placeholder="Example@gmail.com" />
  <input style="position:absolute; top:80%; left:5%; width:40%;" type="text" id="password" placeholder="example: 11223344" />
  <input style="position:absolute; top:90%; left:5%; width:40%;" type="submit" onclick="sendEmail()" />
</form>