Tutorial for HTML5 drag&drop – sortable list

I’ve tried to keep this sample as simple as possible.

If you create a HTML list:

<ul>
  <li draggable="true" ondragover="dragOver(event)" ondragstart="dragStart(event)">Apples</li>
  <li draggable="true" ondragover="dragOver(event)" ondragstart="dragStart(event)">Oranges</li>
  <li draggable="true" ondragover="dragOver(event)" ondragstart="dragStart(event)">Bananas</li>
  <li draggable="true" ondragover="dragOver(event)" ondragstart="dragStart(event)">Strawberries</li>
</ul>

…and the following javascript:

var _el;

function dragOver(e) {
  if (isBefore(_el, e.target))
    e.target.parentNode.insertBefore(_el, e.target);
  else
    e.target.parentNode.insertBefore(_el, e.target.nextSibling);
}

function dragStart(e) {
  e.dataTransfer.effectAllowed = "move";
  e.dataTransfer.setData("text/plain", null); // Thanks to bqlou for their comment.
  _el = e.target;
}

function isBefore(el1, el2) {
  if (el2.parentNode === el1.parentNode)
    for (var cur = el1.previousSibling; cur && cur.nodeType !== 9; cur = cur.previousSibling)
      if (cur === el2)
        return true;
  return false;
}

… you should get a sortable list.

You can try the code on https://codepen.io/crouchingtigerhiddenadam/pen/qKXgap

Please be aware of the following bug in FireFox:
https://developer.mozilla.org/en-US/docs/Web/Events/dragenter

Hope this helps.