JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/jquery-2.1.1.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/backbone.js/1.1.2/backbone-min.js"></script>
  

<body>
<div id="container"><div id="test">test</div></div>
  <hr>
  <section id="todoapp">
    <header id="header">
      <h1>Todos</h1>
      <input id="new-todo" placeholder="What needs to be done?" autofocus>
    </header>
    <section id="main">
      <ul id="todo-list"></ul>
    </section>
  </section>
  <div>

  </div>

JavaScript

$(function (){
  var test = {};
	test.View = Backbone.View.extend({
		el: 'body',
		initialize: function (){
			this.input = $('#new-todo');
		},
		events: {
			'keyup #new-todo': 'check'
		},
		check: function (){
      console.log('!');
			$('#test').html(this.input.val());
		}
	});
	test.view = new test.View();
});