title: “Violation readystatechange handler took 760ms” After Updating Chrome
body: <p>After updating <a href="https://en.wikipedia.org/wiki/Google_Chrome_version_history" rel="nofollow noreferrer">Google Chrome v57.0.2987</a>,
  our website is getting errors when we open <a href="https://www.jacklmoore.com/colorbox/" rel="nofollow noreferrer">Collorbox</a>:</p>
  <pre class="lang-none prettyprint-override"><code>Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check https://xhr.spec.whatwg.org/.
  
      [Violation] 'readystatechange' handler took 760ms
      [Violation] Forced reflow while executing JavaScript took 51ms
      [Violation] Forced reflow while executing JavaScript took 43ms
      [Violation] Forced reflow while executing JavaScript took 38ms
  </code></pre>
  <p>This only happens sometimes. And when we get these errors, Colorbox does not work for us.</p>
  <p>Is there maybe a bug on Google Chrome?</p>
  <p><strong>Edit:</strong>
  <a href="https://magento.com/" rel="nofollow noreferrer">Magento</a> merging JavaScript is causing the error. This is what’s not working right. If I don’t merge them, then I don’t get these errors and it’s loading correctly.</p>
  <pre class="lang-none prettyprint-override"><code>VM23586:4 Uncaught TypeError: Cannot set property 'value' of null  at choose (eval at &lt;anonymous&gt; (0a9e2e3….js:11743), &lt;anonymous&gt;:4:73)  at HTMLImageElement.onclick (letto-moderno-imbottito-prisma.html:1)
  Uncaught TypeError: Cannot read property 'close' of undefined  at HTMLDivElement.onclick (letto-moderno-imbottito-prisma.html:1)
  </code></pre>