Q:

Auto-number table rows?

I have the following HTML table:
<table border="1">
  <tr>
    <td>blue</td>
  </tr>
  <tr>
    <td>red</td>
  </tr>
  <tr>
    <td>black</td>
  </tr>
</table>

I would like each row in this table have a number automatically assigned to each item.
How could he do?

A:

The following CSS enumerates table rows (demo):

table {
  counter-reset: rowNumber;
}

table tr::before {
  display: table-cell;
  counter-increment: rowNumber;
  content: counter(rowNumber) ".";
  padding-right: 0.3em;
  text-align: right;
}
<table cellpadding="0">
  <tr><td>blue</td></tr>
  <tr><td>red</td></tr>
  <tr><td>yellow</td></tr>
  <tr><td>green</td></tr>
  <tr><td>purple</td></tr>
  <tr><td>orange</td></tr>
  <tr><td>maroon</td></tr>
  <tr><td>mauve</td></tr>
  <tr><td>lavender</td></tr>
  <tr><td>pink</td></tr>
  <tr><td>brown</td></tr>
</table>

If the CSS cannot be used, try the following JavaScript code (demo):

var table = document.getElementsByTagName('table')[0],
  rows = table.getElementsByTagName('tr'),
  text = 'textContent' in document ? 'textContent' : 'innerText';

for (var i = 0, len = rows.length; i < len; i++) {
  rows[i].children[0][text] = i + ': ' + rows[i].children[0][text];
}
<table border="1">
  <tr>
    <td>blue</td>
  </tr>
  <tr>
    <td>red</td>
  </tr>
  <tr>
    <td>black</td>
  </tr>
</table>

A:

And if you would use headers as well the following is the thing you need:
http://jsfiddle.net/davidThomas/7RyGX/
table {
    counter-reset: rowNumber;
}

table tr:not(:first-child) {
    counter-increment: rowNumber;
}

table tr td:first-child::before {
    content: counter(rowNumber);
    min-width: 1em;
    margin-right: 0.5em;
}

note the: ":not(:first-child)" in there.

A:

Here is a modification of David Thomas' CSS solution that works with or without a header row in the table. It increments the counter on the first td cell of each row (thereby skipping the row with only th cells):
table
{
    counter-reset: rowNumber;
}

table tr > td:first-child
{
    counter-increment: rowNumber;
}

table tr td:first-child::before
{
    content: counter(rowNumber);
    min-width: 1em;
    margin-right: 0.5em;
}

You can see the behavior in this jsfiddle.

