Сделать ссылку вместо текста jquery

$("td.col1").each(function(el) { 
  let value = $(this).html(); 
  $(this).html('<a href="index.php?id=' + value + '">' + value + '</a>'); 
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> 
 
<table> 
  <tr> 
    <td class="col1">1</td> 
  </tr> 
  <tr> 
    <td class="col1">2</td> 
  </tr> 
  <tr> 
    <td class="col1">3</td> 
  </tr> 
</table>

$('td.col1').each(function() { 
  var innerText = $( this ).text(); 
  $( this ).html('<a href="index.php?id=' + innerText + '">' + innerText +'</a>');   
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> 
<table> 
<tr> 
<td class="col1">1</td> 
</tr> 
<tr> 
<td class="col1">2</td> 
</tr> 
<tr> 
<td class="col1">3</td> 
</tr> 
</table>