var ul = $('#test-div ul');
ul.append('<li><span>Pascal</span></li>');
ul.append('<li><span>Lua</span></li>');
ul.append('<li><span>Ruby</span></li>');
var list = [];
for (var child of ul[0].children) {
    list.push(child);
}
list.sort((x,y) => {
    return x.innerText > y.innerText;
});
for (var li of list) {
    ul.append(li);
}