Question

How can done if all tags ul in .empty is empty alert ok?(with jQuery)

EXAMPLE: http://jsfiddle.net/pqgGr/

<div class="empty">
    <ul>1</ul>
    <ul></ul>
    <ul></ul>
</div>
if ($('.empty ul').is(":empty")) {
    alert('ok')
}

Answer 1

Use :not() to exclude the empty items, and see if that returns an empty collection:

if($('.empty ul:not(:empty)').length == 0) {
   alert('ok');
}

Live demo