2.1.130 Part 1 Section 17.4.17, gridSpan (Grid Columns Spanned by Current Table Cell) 2.1.131 Part 1 Section 17.4.18, header (Header Cell Reference) 2.1.132 Part 1 Section 17.4.19, headers (Header Cells Associated With Table Cell) 2.1.133 Part 1 Section 17.4.20, hidden (Hi...