HTML table highlight row on hover except first row (header)

You can do this using the CSS :hover specifier. Here's a demonstration:

<table>
    <tr><th>Col 1 Head</th><th>Col 2 Head</th></tr>
    <tr class = "notfirst"><td>Data 1</td><td>Data 2</td></tr>
    <tr class = "notfirst"><td>Data 3</td><td>Data 4</td></tr>
</table>

CSS:

.notfirst:hover {
    background-color: red;
}

There is a way to achieve the desired behavior without class-ing each row separately. Here's how to highlight each table row except for first one (header) on hover using the CSS :not and :first-child selectors:

tr:not(:first-child):hover {
    background-color: red;
}

Unfortunately, IE < 9 does not support :not, so to do this in a cross-browser way, you can use something like this:

tr:hover {
    background-color: red;
}
tr:first-child:hover {
    background-color: white;
}

Basically, the first CSS rule includes all rows. To avoid highlighting the first row, you override the its hover style by selecting with tr:first-child and then keeping its background-color to white (or whatever the non-highlighted row's color is).

I hope that helped, too!

To expand on user2458978's answer surely the best way of doing this is to code up the tables correctly.

<table>
<thead>
    <tr><th></th></tr>
</thead>
<tbody>
    <tr><td></td></tr>
    <tr><td></td></tr>
</tbody>
</table>

Then the CSS is simply

table tbody tr:hover { background-color: red; }

Here's a jsFiddle example