Wrap first level of "li" tags into one div using Jquery

Consider we have a multi-level html list that looks like this:

<ul class="catalog">
  <li>
    <ul>
      <li>
        <ul>
          <li>subcat subcat 1</li>
          <li>subcat subcat 2</li>
          <li>subcat subcat 3</li>
        </ul>
      </li>
      <li>subcat 2</li>
      <li>subcat 3</li>
    </ul>
  </li>
  <li>
    <ul>
      <li>开发者_JS百科subcat 4</li>
      <li>subcat 5</li>
      <li>subcat 6</li>
    </ul>
  </li>

</ul>

I need to wrap into one div only <li> tags (hamed "header 1", "header 2"... and all its children) which belong to first level of the list.

The result should be:

<ul class="catalog">
  <div class="myWrapper">
    <!-- Added by JQuery -->
    <li>
      <ul>
        <li>
          <ul>
            <li>subcat subcat 1</li>
            <li>subcat subcat 2</li>
            <li>subcat subcat 3</li>
          </ul>
        </li>
        <li>subcat 2</li>
        <li>subcat 3</li>
      </ul>
    </li>
    <li>
      <ul>
        <li>subcat 4</li>
        <li>subcat 5</li>
        <li>subcat 6</li>
      </ul>
    </li>

  </div>
  <!-- Added by JQuery -->

</ul>

I tried wrap() function but it did not work as expected

Any ideas how to do this job?

$('.catalog > li').wrapAll('<div class="wrapper"></div>');

But you're both starting and ending with seriously invalid HTML, so you should probably fix that then ask this question again.

First, let's start with valid HTML, like this:

<ul class="catalog">
   <li>header 1
      <ul>
        <li>subcat 1
            <ul>
               <li>subcat subcat 1</li>
               <li>subcat subcat 2</li>
               <li>subcat subcat 3</li>
            </ul>
        </li>
        <li>subcat 2</li>
        <li>subcat 3</li>
      </ul>
   </li>
   <li>header 2
      <ul>
        <li>subcat 4</li>
        <li>subcat 5</li>
        <li>subcat 6</li>
      </ul>
    </li>
</ul>​

Then you cap wrap them using .wrapAll(), like this:

$(".catalog > li").wrapAll("<li><div class='something'><ul></ul></div></li>");​

This results in valid HTML, like this:

<ul class="catalog">
  <li>
    <div class="something">
      <ul>
        <li>header 1
          <ul>
            <li>subcat 1
                <ul>
                   <li>subcat subcat 1</li>
                   <li>subcat subcat 2</li>
                   <li>subcat subcat 3</li>
                </ul>
            </li>
            <li>subcat 2</li>
            <li>subcat 3</li>
          </ul>
        </li><li>header 2
          <ul>
            <li>subcat 4</li>
            <li>subcat 5</li>
            <li>subcat 6</li>
          </ul>
        </li>
      </ul>
    </div>
  </li>  
</ul>

You can test it out here, though you can probably get the effect you want with styling on the original <ul>, display: block for example.