title: How can I set the order of loading files in the form for input type="file" multiple?
body: <p>There is a drag file preview area in which I set the key attribute to the pictures. I want, depending on this attribute, to specify the order in which these files appear on the site. How can I pass this attribute on form?</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>$("#fileUpload").change(function() {
    handleFiles(this.files);
  });
  
  function handleFiles(files) {
    for (let i = 0; i &lt; files.length; i++) {
      const file = files[i];
      const img = document.createElement("img");
      let elements = [];
      img.classList.add("obj");
      img.id = i + 1;
      img.file = file;
      $(img).attr('key', i + 1);
      elements = '&lt;li&gt;&lt;span class="img-move"&gt;' + (i + 1) + '&lt;/span&gt;&lt;div class="img-wrapper draggable-element d-' + (i + 1) + '"&gt;&lt;span class="img-delete"&gt;&lt;i class="fa fa-close "&gt;&lt;/i&gt;&lt;/span&gt;&lt;/div&gt;&lt;/li&gt;';
      $('#images').append(elements);
      const reader = new FileReader();
      reader.onload = (function(aImg) {
        return function(e) {
          aImg.src = e.target.result;
        };
      })(img);
      $(`.img-wrapper.d-${i + 1}`).append(img);
      reader.readAsDataURL(file);
    }
  
  }</code></pre>
  </div>
  </div>
  </p>
  
  <p>This is my code for the preview area.</p>