2.1.14 [HTML] Section 11.2.3, Row groups: the THEAD, TFOOT, and TBODY elements

V0014:

The specification states:

 When present, each THEAD, TFOOT, and TBODY contains a row group. Each row group 
 must contain at least one row, defined by the TR element.

Quirks Mode, IE7 Mode, IE8 Mode, and IE9 Mode (All Versions)

THEAD, TFOOT, and TBODY are not required to contain a row defined by the TR element.

V0015:

The specification states:

 The TBODY start tag is always required except when the table contains only one 
 table body and no table head or foot sections.

All Document Modes (All Versions)

The TBODY start tag is always optional and will be implied for any TR elements that are direct children of a TABLE element.