固定表格标题-表格内容滚动

<style type="text/css">
#athoritytab td{border:solid 1px #c5d9e9; border-top:0; border-bottom:0; border-left:0 } /*设置表格边框*/
</style>

<table width="500" border=1>
    <tr>
        <td>title1</td>
        <td>title2</td>
        <td>title3</td>
        <td>title4</td>
        <td>title5</td>
        <td>&nbsp;</td>
    </tr>
    <tr>
        <td colspan="6">
        <div style="overflow:auto;height:50px;">
        <table border="1" width="100%" id="athoritytab">
            <tr>
                <td>A</td>
                <td>B</td>
                <td>C</td>
                <td>D</td>
                <td>E</td>
            </tr>
            <tr>
                <td>A1</td>
                <td>B1</td>
                <td>C1</td>
                <td>D1</td>
                <td>E1</td>
            </tr>
            <tr>
                <td>A2</td>
                <td>B2</td>
                <td>C2</td>
                <td>D2</td>
                <td>E2</td>
            </tr>                        
        </table>
        </div>
        </td>
    </tr>
</table>