JSFiddle - React, Tailwind, and code Playground
HTML
<form id="content-add-form" role="form" name="content-add-form" enctype="multipart/form-data">
<input type="text" name="foo" value="foo"/>
<form>
JavaScript
var formData = new FormData($('#content-add-form')[0]);
var xhr = new XMLHttpRequest;
xhr.open('POST', '/');
xhr.send(formData);