Setting a max height on a table

NOTE this answer is now incorrect. I may get back to it at a later time.

As others have pointed out, you can’t set the height of a table unless you set its display to block, but then you get a scrolling header. So what you’re looking for is to set the height and display:block on the tbody alone:

<table style="border: 1px solid red">
    <thead>
        <tr>
            <td>Header stays put, no scrolling</td>
        </tr>
    </thead>
    <tbody style="display: block; border: 1px solid green; height: 30px; overflow-y: scroll">
        <tr>
            <td>cell 1/1</td>
            <td>cell 1/2</td>
        </tr>
        <tr>
            <td>cell 2/1</td>
            <td>cell 2/2</td>
        </tr>
        <tr>
            <td>cell 3/1</td>
            <td>cell 3/2</td>
        </tr>
    </tbody>
</table>

Here’s the fiddle.