<!-- SGML standard forces different NAMES for all attribute values
in the same element, regardless of the attribute name! As a result
CDATA is used for CLEAR attribute to avoid clash with ALIGN
<!ENTITY % needs -- Attributes for controlling text flow. Used in headers
and other elements to guarantee sufficient room --
'clear CDATA "no" -- (left|right|all|no) move down past figures --
One alternative might be:
clear (c_left|c_center|c_right) #IMPLIED
I'm not sure if the underscore is legal.
The problem with the CDATA method is that HTML editors that
are working from the DTD can't provide a menu of choices to the
user. The SGML parser is also prevented from validating the values
of the clear attribute.