SO - 18470835

by Tilwin Joy

HTML

<ul id="list" class="simplelist">
  <li class="sortable-item valid">
  </li>
  <li class="sortable-item valid">
  </li>
  <li class="sortable-item">
  </li>
</ul>

CSS

li {
  list-style-type: none;
  height: 50px;
  margin: 5px;
  background: dodgerblue;
}

JavaScript

$("#list").sortable({
  cancel: ':not(.valid)'
});