Form The Win!

ftw.html

<script>
  function formRequest(method, action, body) {
    event.preventDefault();
    fetch(action, { method, body })
      .then(res => res.redirected ? location.href = res.url : res.text())
      .then(document.write.bind(document));
  }
  const PUT = form => formRequest("PUT", form.action, new FormjData(form));
  const DELETE = form => formRequest("DELETE", form.action);
</script>

<form action="/">
  <input type="text" name="title" />
  <input type="submit" value="GET" />
</form>

<form action="/" method="POST">
  <input type="text" name="title" />
  <input type="submit" value="POST" />
</form>

<form action="/" onsubmit="PUT(this)">
  <input type="text" name="title" />
  <input type="submit" value="PUT" />
</form>

<form action="/id1" onsubmit="DELETE(this)">
  <input type="text" name="title" />
  <input type="submit" value="DELETE" />
</form>