filter div jquery

1<ul>
2  <li><strong>list</strong> item 1 - one strong tag</li>
3  <li><strong>list</strong> item <strong>2</strong> -
4    two <span>strong tags</span></li>
5  <li>list item 3</li>
6  <li>list item 4</li>
7  <li>list item 5</li>
8  <li>list item 6</li>
9</ul>
10