title: CORS blocked in MS Edge but works in All other browsers
body: <h3>The setup:</h3>
  <ul>
  <li>Website is attempting to download a file from S3 (could be any server with properly configured CORS policies)</li>
  <li>Attempting to download a file using <a href="https://github.com/eligrey/FileSaver.js" rel="nofollow noreferrer">FileSaver.js</a>: <code>download(&quot;https://s3url.com/path/you/do/not/need/to/no.jpeg&quot;)</code></li>
  <li>Under the hood FileSaver.js is doing this:</li>
  </ul>
  <pre><code>var xhr = new XMLHttpRequest()
  xhr.open('GET', url)
  </code></pre>
  <ul>
  <li>Chrome and FF work fine.</li>
  <li>S3 CORS policy is wide open</li>
  </ul>
  <pre><code>[
      {
          &quot;AllowedHeaders&quot;: [
              &quot;*&quot;
          ],
          &quot;AllowedMethods&quot;: [
              &quot;GET&quot;,
              &quot;PUT&quot;,
              &quot;POST&quot;,
              &quot;DELETE&quot;,
              &quot;HEAD&quot;
          ],
          &quot;AllowedOrigins&quot;: [
              &quot;*&quot;
          ],
          &quot;ExposeHeaders&quot;: []
      }
  ]
  </code></pre>
  <h3>The Issue</h3>
  <p>In MS Edge* only, using <a href="https://github.com/eligrey/FileSaver.js" rel="nofollow noreferrer">FileSaver.js</a>, any attempt to save a resource in S3 fails with <code>blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.</code></p>
  <ul>
  <li>Edge Version 90.0.818.56 (Official build)</li>
  </ul>