scegli la piu appropriata

codice:
<html>
<head>
<style>
</style>
<script>
function hiddenCol(theIndex)
  {
  //alert(theIndex);
  var myTable=document.getElementById('lista_gente');
  for (var x=1; x < myTable.rows.length; x++) 
    {
    if (myTable.rows[x].cells[theIndex].style.visibility =='hidden')
        myTable.rows[x].cells[theIndex].style.visibility ='';  
    else
        myTable.rows[x].cells[theIndex].style.visibility ='hidden';
    }
  }

function deleteCol(theIndex)
  {
  //alert(theIndex);
  var myTable=document.getElementById('lista_gente2');
  for (var x=0; x < myTable.rows.length; x++) 
    {   
    myTable.rows[x].deleteCell(theIndex);
    }
  }

</script>
</head>
<body>
<table border="1" id="lista_gente">
<tr>
  <td>Nome</td>
  <td>Cognome</td>
  <td>Eta</td>
</tr>
<tr>
  <td>Pippo</td>
  <td>Caio</td>
  <td>12</td>
</tr>
<tr>
  <td>Max</td>
  <td>Biaggione</td>
  <td>34</td>
</tr>
<tr>
  <td>Pippo</td>
  <td>Anastasio</td>
  <td>57</td>
</tr>
</table>



<table border="1" id="lista_gente2">
<tr>
  <td>Nome</td>
  <td>Cognome</td>
  <td>Eta</td>
</tr>
<tr>
  <td>Pippo</td>
  <td>Caio</td>
  <td>12</td>
</tr>
<tr>
  <td>Max</td>
  <td>Biaggione</td>
  <td>34</td>
</tr>
<tr>
  <td>Pippo</td>
  <td>Anastasio</td>
  <td>57</td>
</tr>
</table>
</body>
</html>