html 单元格合并

<table border="1" style={{margin:200}}>

<tbody>

<tr>

    <th colspan="2">我是占位符</th>

    <th colspan="2">我是占位符</th>

</tr>

<tr>

    <th rowspan="2">我是占位符</th>

    <th>我是占位符</th>

    <th>我是占位符</th>

    <th>我是占位符</th>

</tr>

<tr>

    <th>我是占位符</th>

    <th>我是占位符</th>

    <th>我是占位符</th>

</tr>

</tbody>

        </table>