children、html、contents等jQuery方法遍历的区别

<div id='father'>
    <ul id='ul'>
        <li class="li">一</li>
        <li class="li">二</li>
        <li class="li">三</li>
        <li class="li">四</li>
        <li class="li">五</li>
    </ul>
</div>

#

//children():返回被选元素的所有直接子元素
$('#father').children(); //#ul

//html():