效果：
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>
</title>
<style>
table{
border-collapse:collapse;
border:none;
}
table:hover{
cursor:pointer;
}
th, td
{
border: 1px solid black;
}
.dd{
100px;
height: 100px;
background-color:red;
border-radius: 50%;
-moz-border-radius: 50%;
-webkit-border-radius: 50%;
}
</style>
</head>
<body>
<table>
<tr>
<td><div class="dd"></div></td>
<td><div class="dd"></div></td>
</tr>
<tr>
<td><div class="dd"></div></td>
<td><div class="dd"></div></td>
</tr>
</table>
</body>
</html>