[CSS] [proprietà] border-collapse

Esempi

<style>
table#border_separate {
    border-collapse: separate;
}
table#border_collapse {
    border-collapse: collapse;
}
table, td, th {
    border: 1px solid black;
}
</style>

<table id="border_separate">
  <tr>
    <th>1</th>
    <th>2</th>
  </tr>
  <tr>
    <td>3</td>
    <td>4</td>
  </tr>
</table>
<table id="border_collapse">
  <tr>
    <th>5</th>
    <th>6</th>
  </tr>
  <tr>
    <td>7</td>
    <td>8</td>
  </tr>
</table>