边框合并

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>Document</title>
 6     <style type="text/css">
 7         table{
 8             width:200px;
 9             height:200px;
10             border:1px solid red;
11             border-collapse:collapse;
12         }
13         td{
14             border:1px solid red;
15             
16         }
17     </style>
18 </head>
19 <body>
20     <table cellspacing="0">
21         <tr>
22             <td></td>
23             <td></td>
24             <td></td>
25         </tr>
26         <tr>
27             <td></td>
28             <td></td>
29             <td></td>
30         </tr>
31         <tr>
32             <td></td>
33             <td></td>
34             <td></td>
35         </tr>
36     </table>
37 </body>
38 </html>
边框合并：border-collapse:collapse;