第二层的div无法撑开第一层div

[wxcnl1]

table.center,div.center
{
margin-left:2%;
margin-right:2%;
width:96%;
min-width:240px;
max-width:480px;
max-height:320px;
}

div.outLine {
border-style:none;
padding:0px;
margin:0px;
border-collapse:collapse;
min-width:240px;
max-width:480px;
max-height:320px;
}
<div id="FirstLevel" style="border-bottom: 1px solid; border-left: 1px solid; border-top: 1px solid;
border-right: 1px solid;position:static" class="outLine">

<div id="SecondLevel" class="content">
<table class="center">
<tbody>

<tr class="odd">
<td>
<div class="tag2">
<a href="http://localhost:2891/default.aspx?id=00000000-0000-0000-0000-000000000211&display=summary">
uuuuuuuuuuuuu uuuuuuuuuuuuuuuuu uuuuuuuuuuuuuuuuuuuu uuuuuuuuuuuuu uuuuuuuuuuuuuuuuuuuu
4563456256</a>
</div>
</td>

</tr>
</tbody>
</table>
</div>
</div>

[wxcnl1]

?????????????????????

[wxcnl1]

希望能够像表格一样，相应的撑开，里层撑开外层

[MSDNXGH]

第一个DVI高度设为auto

[zzxap]

clear:both

[zzxap]

<div id="FirstLevel" style="border-bottom: 1px solid; border-left: 1px solid; border-top: 1px solid;
border-right: 1px solid;position:static" class="outLine">

<div id="SecondLevel" class="content">
<table class="center">
<tbody>

<tr class="odd">
<td>
<div class="tag2">
<a href="http://localhost:2891/default.aspx?id=00000000-0000-0000-0000-000000000211&display=summary">
uuuuuuuuuuuuu uuuuuuuuuuuuuuuuu uuuuuuuuuuuuuuuuuuuu uuuuuuuuuuuuu uuuuuuuuuuuuuuuuuuuu
4563456256</a>
</div>
</td>

</tr>
</tbody>
</table>
<div class="clear" style="clear:both"></div>
</div>
<div class="clear" style="clear:both"></div>
</div>

[wxcnl1]

为什么要多加两个div？<div class="clear" style="clear:both"></div>
为什么不在原来的div上加clear:both？