<script>

var contactForm = document.querySelector('form'),
inputEmail = contactForm.querySelector('[name="email"]'),
textAreaMessage = contactForm.querySelector('[name="content"]'),
sendButton = contactForm.querySelector('button');

sendButton.addEventListener('click', function(event){
  event.preventDefault();

  sendButton.innerHTML = '{{ site.text.contact.ajax.sending }}';

  var xhr = new XMLHttpRequest();
  xhr.open('POST', '//formspree.io/{{ site.email }}', true);
  xhr.setRequestHeader("Accept", "application/json")
  xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded")

  xhr.send(
    "email=" + inputEmail.value +
    "&message=" + textAreaMessage.value);

  xhr.onloadend = function (res) {
    if (res.target.status === 200){
      sendButton.innerHTML = '{{ site.text.contact.ajax.sent }}';
    }
    else {
      sendButton.innerHTML = '{{ site.text.contact.ajax.error }}';
    }
  }
});

</script>