potresti usare html 3.2 anche se non credo che funzionerebbe
oppure ricordarti che
DO ensure that if tbody elements are omitted from table elements, scripts that examine the document tree are capable of working both with and without the element.
e poi
DO use explicit tbody elements within tables.
Rationale: While the content model of the table element permits the tbody element to be skipped, in HTML 4 this element is implicit. HTML 4 user agents will silently add this element, thus potentially confusing scripts or style sheets.