tbody添加垂直滚动条

法一：

用2个table：

<table width="300" border="0" cellpadding="0" cellspacing="1" bgcolor="#0099CC">
<tr>
<th width="25%" nowrap><font color="#FFFFFF"> 123 </th>
<th width="25%" nowrap><font color="#FFFFFF"> 456 </th>
<th width="25%" nowrap><font color="#FFFFFF"> 789 </th>
<th width="25%" nowrap><font color="#FFFFFF"> abc </th>
</tr>
</table>
<span style="overflow-y:auto;height:100px;width:320px">
<table width="300" border="0" cellpadding="0" cellspacing="1" bgcolor="#0099CC">
<tr bgcolor="#FFFFFF">
<td width="25%"> 1</td>

<td width="25%"> 4</td>

<td width="25%"> 7</td>

<td width="25%"> a</td>
</tr>

<tr bgcolor="#FFFFFF">
<td > 2</td>

<td > 5</td>

<td> 8</td>

<td> b</td>
</tr>

<tr bgcolor="#FFFFFF">
<td> 3 </td>

<td> 6 </td>

<td> 9 </td>

<td > c </td>
</tr>
<tr bgcolor="#FFFFFF">
<td> 3 </td>

<td> 6 </td>

<td> 9 </td>

<td > c </td>
</tr>
<tr bgcolor="#FFFFFF">
<td> 3 </td>

<td> 6 </td>

<td> 9 </td>

<td > c </td>
</tr>
<tr bgcolor="#FFFFFF">
<td> 3 </td>

<td> 6 </td>

<td> 9 </td>

<td > c </td>
</tr>
<tr bgcolor="#FFFFFF">
<td> 3 </td>

<td> 6 </td>

<td> 9 </td>

<td > c </td>
</tr>
<tr bgcolor="#FFFFFF">
<td> 3 </td>

<td> 6 </td>

<td> 9 </td>

<td > c </td>
</tr>
<tr bgcolor="#FFFFFF">
<td> 3 </td>

<td> 6 </td>

<td> 9 </td>

<td > c </td>
</tr>
<tr bgcolor="#FFFFFF">
<td> 3 </td>

<td> 6 </td>

<td> 9 </td>

<td > c </td>
</tr>
<tr bgcolor="#FFFFFF">
<td> 3 </td>

<td> 6 </td>

<td> 9 </td>

<td > c </td>
</tr>
<tr bgcolor="#FFFFFF">
<td> 3 </td>

<td> 6 </td>

<td> 9 </td>

<td > c </td>
</tr>
</table>
</span> 

法二：

1，把tbody设置成display:block，然后就对其高度设置一个固定值，overflow设置成auto。

2，把thead的tr设置成display:block。

3，因为都设置成block所以要给td手动添加宽度 width:200px

<table class="table">
<thead>
<tr>
<th>Id</th>
<th>Name</th>
<th>Category</th>
<th>MonthAmount</th>
<th>hasBackUp</th>
<th>score</th>
</tr>
</thead>
<tbody>
<tr>
<td>23</td>
<td>South Bearing</td>
<td>Glass/Material</td>
<td>1234444</td>
<td>TRUE</td>
<td>3456.00</td>
</tr>
<tr>
<td>23</td>
<td>South Bearing</td>
<td>Glass/Material</td>
<td>1234444</td>
<td>TRUE</td>
<td>3456.00</td>
</tr>
<tr>
<td>23</td>
<td>South Bearing</td>
<td>Glass/Material</td>
<td>1234444</td>
<td>TRUE</td>
<td>3456.00</td>
</tr>
<tr>
<td>23</td>
<td>South Bearing</td>
<td>Glass/Material</td>
<td>1234444</td>
<td>TRUE</td>
<td>3456.00</td>
</tr>
<tr>
<td>23</td>
<td>South Bearing</td>
<td>Glass/Material</td>
<td>1234444</td>
<td>TRUE</td>
<td>3456.00</td>
</tr>
<tr>
<td>23</td>
<td>South Bearing</td>
<td>Glass/Material</td>
<td>1234444</td>
<td>TRUE</td>
<td>3456.00</td>
</tr>
<tr>
<td>23</td>
<td>South Bearing</td>
<td>Glass/Material</td>
<td>1234444</td>
<td>TRUE</td>
<td>3456.00</td>
</tr>
<tr>
<td>23</td>
<td>South Bearing</td>
<td>Glass/Material</td>
<td>1234444</td>
<td>TRUE</td>
<td>3456.00</td>
</tr>
<tr>
<td>23</td>
<td>South Bearing</td>
<td>Glass/Material</td>
<td>1234444</td>
<td>TRUE</td>
<td>3456.00</td>
</tr>
<tr>
<td>23</td>
<td>South Bearing</td>
<td>Glass/Material</td>
<td>1234444</td>
<td>TRUE</td>
<td>3456.00</td>
</tr>
<tr>
<td>23</td>
<td>South Bearing</td>
<td>Glass/Material</td>
<td>1234444</td>
<td>TRUE</td>
<td>3456.00</td>
</tr>
</tbody>
</table> 

.table thead tr {
display:block;
}
.table tbody {
display: block;
height: 200px;
overflow: auto;
}
.table th {
width:20%;
}
.table td {
width:20%;
}