alert print table tr/td width to 460px

<fieldset style="margin:30px">
<legend><font color="#296B3C" style="font-family:黑体">初善仪<SUP>&reg;</SUP>宫颈癌筛查系统检查内容</font></legend>
<span  width="50%" style="float:left" >
<table style="clear:left;max-width:460px;width:460px;vertical-align:middle;height:400px">
<tr style="height:10px"></tr>
<tr><td>