Adding level depth to class of nested lists

I have nested lists like this:

 <ul>
         <li>item 1</li>
         <li>item 2
             <ul>
         开发者_Go百科       <li>subitem 1</li>
                <li>subitem 2</li>
                    <ul>
                       <li>sub-subitem1</li>
                    </ul>
                </li>
             </ul>
        </li>
        <li>item 3
            <ul>
                <li>subitem 1</li>
            </ul>
        </li> 
    </ul>

Is there any way I could add a class to the based on their depth level so the output is something like this?

<ul class="level-0">
     <li>item 1</li>
     <li>item 2
         <ul class="level-1">
            <li>subitem 1</li>
            <li>subitem 2</li>
                <ul class="level-2">
                   <li>sub-subitem1</li>
                </ul>
            </li>
         </ul>
    </li>
    <li>item 3
        <ul class="level-1">
            <li>subitem 1</li>
        </ul>
    </li> 
</ul>

I am new to jQuery, have tried this:

$("ul").each(function(index, element){$(element).attr("class", "level-" + index);});

...but it only counts the ul's based on their index. Any help is much appreciated!

---

Try this:

$('ul').each(function() {
    var depth = $(this).parents('ul').length;
    $(this).addClass('level-' + depth);
});

See http://jsfiddle.net/alnitak/YSZFm/

---

If you only have 3 levels, try this:

$('ul').addClass('level-0');
$('ul').find('ul').removeClass('level-0').addClass('level-1');
$('ul').find('ul').find('ul').removeClass('level-0').removeClass('level-1').addClass('level-2');

http://jsfiddle.net/fallen888/2rATE/

For a more dynamic solution, try this:

$("ul").each(function(index, element) {
    var parents = $(this).parents('ul');
    var level = -1;

    if (parents.length > 0) {
        var parentClass = $(parents.get(0)).attr('class');
        level = parseInt(parentClass.substr(parentClass.indexOf('level-') + 6, 1));
    }

    $(this).addClass('level-' + (level + 1));
});

http://jsfiddle.net/fallen888/2rATE/1/