http://swissnet.ai.mit.edu/~jaffer/validator-bug
validator-bug
According to the HTML 3.2 Reference Specification:
HTML allows CDATA attributes to be unquoted provided the attribute
value contains only letters (a to z and A to Z), digits (0 to 9),
hyphens (ASCII decimal 45) or, periods (ASCII decimal 46). Attribute
values can be quoted using double or single quote marks (ASCII decimal
34 and 39 respectively). Single quote marks can be included within
the attribute value when the value is delimited by double quote marks,
and vice versa.
But validator.w3.org does not catch this error: