Am Freitag, 20. Januar 2006 14:54 schrieb Graham Fawcett:
> Titus Brown wrote:
>     "By default, SGML requires that all attribute values be delimited
>     using either double quotation marks (ASCII decimal 34) or single
>     quotation marks (ASCII decimal 39).
[cut]
> Don't have a ref at hand, but I am certain it's valid in XML as well.

Yes, XML allows single and double quotation marks:

AttValue           ::=          '"' ([^<&"] | Reference)* '"'
                        |  "'" ([^<&'] | Reference)* "'"

https://www.w3.org/TR/2004/REC-xml-20040204/#NT-AttValue

 Thomas