To set focus on first text field with Prototype I prefer something like this

  var firstField = $$('input:text:visible').first();
  if (firstField)
    firstField.focus();

but you can also try with Form.focusFirstElement or Form.findFirstElement

HTML for our table will look like

<table class="zebra">
  <thead>
    <tr>
      <th>Col1</th>
      <th>Col2</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>11</td>
      <td>12</td>
    </tr>
    <tr>
      <td>21</td>
      <td>22</td>
    </tr>
    <tr>
      <td>31</td>
      <td>32</td>
    </tr>
  </tbody>
</table>

We will also need some CSS to change the background of the even rows and to highlight the row mouse is over

table.zebra tr.even {
  background-color:#eee;
}
table.zebra tr:hover {
  background-color:#ccc;
}

And now all we need is as simple as

$$('table.zebra tbody tr:nth-child(even)').each(function(tr) {
  tr.addClassName('even');
});

One thing to notice is that tr:hover selector won’t work in IE 6. If you care about IE6, solution could be to observe row for mouseover event and to add hover class dynamically.

You should add

$$('table.zebra tbody tr').each(function(tr) {
  tr.observe('mouseover', function() {
    tr.addClassName('hover');
  }
});

and change table.zebra tr:hover to

table.zebra tr.hover {
  background-color:#ccc;
}

Looks like this won’t be a last post devoted to Prototype