给table加边框的样式

<style>
.tb
{
     width: 1600px; 
     text-align: center;
     border-collapse: collapse;
}
.tb tr td
{
    border:1px solid #dcdddd;
}
</style>

<table class="tb" cellpadding="0" cellspacing="0">
    <tr>
        <td>aaa</td>
        <td>bbc</td>
        <td>ccc</td>
    </tr>
    <tr>
        <td>aaa</td>
        <td>ddd</td>
        <td>eee</td>
    </tr>
    <tr>
        <td>ddd</td>
        <td>ddd</td>
        <td>ddd</td>
    </tr>
</table>