解决ul显示不在div中的问题

        #banner
        {
            padding: 0px;
        }
        #banner ul
        {
            list-style: none;
            margin: 0px;
            padding: 0px;
            text-align: left;
        }
        #banner li
        {
            min-width: 55px;
            float: left;
        }
        .clear
        {
            clear: both;
        }

    <div id="banner">
        <ul>
            <li>1</li>
            <li>2 </li>
            <li>3 </li>
            <li>4</li>
            <li>5</li>
        </ul>
        <ul class=" clear">
        </ul>
    </div>