var ul = $("#test-div ul");
ul
  .append("<li><span>Pascal</span></li>")
  .append("<li><span>Lua</span></li>")
  .append("<li><span>Ruby</span></li>");
var sli = ul.find("li");
sli.sort((a, b) => {
  a = a.innerHTML;
  b = b.innerHTML;
  return a.localeCompare(b);
});
ul.append(sli);