可能重复：
CSS 使空单元格的边框出现？
我知道这个问题以前被问过很多次，我尝试在每个 <td> </td>标签之间添加 ，但效果不佳，我猜 CSS 中存在某种问题，但我无法发现它，我的表格在 Firefox 和 Chrome 上显示正常，但每当我尝试使用 IE8 时，都会缺少一些边框。下面是 HTML 和表格的 CSS，以及屏幕截图。表格的 HTML 是从 PHP 脚本生成的。
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<!--[if IE]>
<link rel ="stylesheet" type ="text/css" href ="layout_ie.css"/>
<![endif]-->
<!--[if !IE]> -->
<link rel ="stylesheet" type ="text/css" href ="layout.css"/>
<!-- <![endif]-->
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
<title>Calendario de Capacitaciones</title>
</head>
<body>
<table cellpadding="0" cellspacing="0" class="calendar">
<tr class = "calendar-row">
<td class = "calendar-day-head">Lunes</td>
<td class = "calendar-day-head">Martes</td>
<td class = "calendar-day-head">Miércoles</td>
<td class = "calendar-day-head">Jueves</td>
<td class = "calendar-day-head">Viernes</td>
<td class = "calendar-day-head">Sábado</td>
<td class = "calendar-day-head">Domingo</td>
</tr>
<tr class = "calendar-row">
<td class ="calendar-day-np"> </td>
<td class ="calendar-day-np"> </td>
<td class ="calendar-day-np"> </td>
<td class ="calendar-day-np"> </td>
<td class ="calendar-day-np"> </td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">1</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">2</div><p> </p><p> </p> 
</td>
</tr>
<tr class="calendar-row">
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">3</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">4</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">5</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">6</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">7</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">8</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">9</div><p> </p><p> </p> 
</td>
</tr>
<tr class="calendar-row">
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">10</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">11</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">12</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day">
 <div class = "day-number">13</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">14</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">15</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">16</div><p> </p><p> </p> 
</td>
</tr>
<tr class="calendar-row">
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">17</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">18</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">19</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">20</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">21</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">22</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">23</div><p> </p><p> </p> 
</td>
</tr>
<tr class="calendar-row">
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">24</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">25</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">26</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">27</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">28</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">29</div><p> </p><p> </p> 
</td>
<td bgcolor="#FFFFFB" class = "calendar-day"> 
<div class = "day-number">30</div><p> </p><p> </p> 
</td>
</tr>
<tr class="calendar-row">
<td bgcolor="#FFFFFB" class = "calendar-day">
 <div class = "day-number">31</div><p> </p><p> </p> 
</td>
<td class = "calendar-day-np"> </td>
<td class = "calendar-day-np"> </td>
<td class = "calendar-day-np"> </td>
<td class = "calendar-day-np"> </td>
<td class = "calendar-day-np"> </td>
<td class = "calendar-day-np"> </td>
</tr>
</table>
</body>
</html>
CSS
table.calendar {table-layout:fixed;margin-top:5em ;margin-left:15em; border-left:1px solid #999; }
tr.calendar-row { }
td.calendar-day { min-height:80px; font-size:11px; position:relative;border:1px solid #999; } * html div.calendar-day { height:80px; }
td.calendar-day:hover { background:#eceff5; }
td.calendar-day-np { background:#eee; min-height:80px; } * html div.calendar-day-np { height:80px; }
td.calendar-day-head { background:#ccc; font-weight:bold; text-align:center; width:135px; padding:5px; border-bottom:1px solid #999; border-top:1px solid #999; border-right:1px solid #999; }
div.day-number { background:#999; padding:5px; color:#fff; font-weight:bold; float:right; margin:-5px -5px 0 0; width:20px; text-align:center; }
/* shared */
td.calendar-day, td.calendar-day-np { max-width:50px; padding:5px; border-bottom:1px solid #999; border-right:1px solid #999; }
截图：
它在 IE8 中的外观。
它应该是什么样子，（取自 Firefox）。
