JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<label for="week">
  <button>
    <span class="glyphicon glyphicon-calendar"></span>
  </button>
</label>
<input type="week" id="week">

JavaScript

var input = document.getElementById('week');

console.log(input);