2.1.2 [W3C-RUBY] Section 2.6, The rt element
V0002:
The specification states:
The rt element may contain inline elements or character data as its content, but the ruby element is not allowed as its descendant element.
All Document Modes (All Versions)
The ruby element is allowed as a descendent element to the rt element.
V0003:
The specification states:
In complex ruby markup, the rbspan attribute allows an rt element to span multiple
rb elements. The value shall be an integer value greater than zero ("0"). The
default value of this attribute is one ("1"). The rbspan attribute should not be
used in simple ruby markup, and user agents should ignore the rbspan attribute when
it appears in simple ruby markup.All Document Modes (All Versions)
The rbspan attribute is not supported in rt elements.
