JH: <th>和<td>标签的区别.

<table width="400px" border="1" cellpadding="1" cellspacing="1">

<caption>学生成绩表</caption>

<tr><th>学号</th><th>期中</th><th>期末</th><th>总评</th></tr>

<tr><td>20094401</td><td>80</td><td>90</td><td>100</td></tr>

<tr><td>20094402</td><td>70</td><td>88</td><td>95</td></tr>

<tr><td>20094403</td><td>90</td><td>92</td><td>90</td></tr>

<tr><th>备注</th><td colspan="3">所有学生考核合格</td></tr>

</table>