[Deff]

<script src="http://code.jquery.com/jquery-latest.js"></script>


<div id="spisok">
      <ul>
            <li>1</li>
            <li>2</li>
            <li>3</li>
            <li>4</li>
            <li>5</li>
            <li>6</li>
            <li>7</li>
            <li>8</li>
            <li>9</li>
            <li>10</li>
     </ul>
</div>



<script type="text/javascript">
var len = $("#spisok > ul > li").length;
alert(len);
</script>