CSS3 counters can be used to number table rows automatically. We need to maintain a counter per row and display it using ::before on first td of every row. Here is code snippet for this.
<style type="text/css">
table {
width: 50%;
counter-reset: row-num;
}
table tr {
counter-increment: row-num;
}
table tr td:first-child::before {
content: counter(row-num) ". ";
}
</style>
<table border=1>
<tr><td></td><td>one</td></tr>
<tr><td></td><td>two</td></tr>
<tr><td></td><td>three</td></tr>
</table>
