Which elements are "valid" to place inside <td> tag?

Question

I know that it's not a good idea to place div inside td, but what about span and other elements? Which elements are ok to place inside td and which are not and why?

Edit: The problem is that I have an old table layout and I need to make modifications there. To do so, I need to add elements inside td, so what elements will be the least evil to insert into <td>?

Answer 1

The HTML spec specifies which elements may be direct decendants of other elements.

The <td> element has a flow content content model, which means it can contain:

a abbr address area (if it is a descendant of a map element) article aside audio b bdi bdo blockquote br button canvas cite code command datalist del details dfn dialog div dl em embed fieldset figure footer form h1 h2 h3 h4 h5 h6 header hgroup hr i iframe img input ins kbd keygen label map mark math menu meter nav noscript object ol output p pre progress q ruby s samp script section select small span strong style (if the scoped attribute is present) sub sup svg table textarea time u ul var video wbr text