title: js utf-8 encoding different than php for heart emoji
body: <p>I want to encode a string with a heart ❤ emoji in js:</p>
  
  <p>php utf8_encode produces: <code>\u2764</code></p>
  
  <p>js utf8.encode produces: <code>â¤</code></p>
  
  <p>are both values valid when I use them in a response with utf header:</p>
  
  <pre><code>"Content-Type": "application/x-www-form-urlencoded; charset=utf-8"
  </code></pre>