html table border

<table>
  <thead>
    <tr>
      <th>header1</th>
      <th>header2</th>
      <th>header3</th>
    </tr>
   </thead>
   <tbody>
     <tr>
       <td>text1.1</td>
       <td>text1.2</td>
       <td>text1.3</td>
     </tr>
     <tr>
       <td>text2.1</td>
       <td>text2.2</td>
       <td>text2.3</td>
     </tr>
     <tr>
       <td>text3.1</td>
       <td>text3.2</td>
       <td>text3.3</td>
     </tr>
     <tr>
     </tr>
  </tbody>
</table>

table, th, td {
  border: 1px solid black;
}

<table style="width:100%"> 
  <tr>
      <th>Firstname</th>
      <th>Lastname</th> 
      <th>Age</th>
  </tr>
  <tr>
      <td>Jill</td>
      <td>Smith</td> 
      <td>50</td>
  </tr>
  <tr>
      <td>Eve</td>
      <td>Jackson</td> 
      <td>94</td>
  </tr>
</table>
 

<table>
  <tr> <!-- This is the first row -->
    <th>This is the heading</th>
    <th>Next heading to the right</th>
  </tr>
  <tr> <!-- This is the second row -->
    <td>This is where the table data goes</td>
    <td>This is the second columns data</td>
  </tr>
</table>

    <table style="width:400px">
    </table> 

    <table>

       
      <tr>

         
      <th>Month</th>

         
      <th>Savings</th>

       
      </tr>

       
      <tr>

         
      <td>January</td>

         
      <td>$100</td>

       
      </tr>

      </table>
 

#customers td, #customers th {
  border: 1px solid #ddd;
  padding: 8px;
}

#customers tr:nth-child(even){background-color: #f2f2f2;}

#customers tr:hover {background-color: #ddd;}

#customers th {
  padding-top: 12px;
  padding-bottom: 12px;
  text-align: left;
  background-color: #4CAF50;
  color: white;
}

<table>
  <tr>
<td>1</td>
  </tr>
  <tr>
    <th>2</th>
  </tr>
</table>  

.centerTable { margin: 0px auto; }

<table style="width:100%">
 
<tr>
    <th>Firstname</th>

    <th>Lastname</th> 
    <th>Age</th>

 
</tr>
 
<tr>
    <td>Jill</td>

    <td>Smith</td> 
    <td>50</td>

 
</tr>
  <tr>
    <td>Eve</td>

    <td>Jackson</td> 
    <td>94</td>

  </tr>
</table>