Does a table cell have a containing block?

Question

According to http://www.w3.org/TR/CSS2/visudet.html, some elements can have a "containing block". Does a table cell td have a containing block, like tr?

e.g.

<div>
    <table>
        <tr>
            <td>hi</td>
        </tr>
    </table>
</div>

Answer 1

The section linked to above says:

2. For other elements, if the element's position is 'relative' or 'static', the containing block is formed by the content edge of the nearest block container ancestor box.

Now, a table-row box is not a block container box because it only contains table-cell boxes, which are not block-level boxes. Neither is a table a block container box because it can only contain other types of boxes, none of which are block-level (e.g. row groups).

Looking at the section on tables, the only references to a containing block in that section refer to the containing block of a table, not a table-cell.

Based on this, it's probably safe to assume that the containing block of a table-cell box or any other internal table box is the same as the containing block of the table in which it resides (which, in your example, is the div). A more conservative reader might prefer to assume that the containing block of any internal table box is undefined.