values of requiredExtensions to use XHTML/MathML

Hello,

In the "Guidelines for Graphics in MathML 2", Michael Kohlhase gives an example
where he uses a foreignObject to include mathematical formulae inside SVG
graphics, in combination with a <switch/> to provide an alternate text. The
requiredExtensions has the value "http://www.w3.org/1998/Math/MathML":

http://www.w3.org/Math/Documents/Notes/graphics.xml#mathml-in-svg-guidelines

Similarly, when Amaya creates XHTML content in SVG, a
requiredExtensions="http://www.w3.org/1999/xhtml" is attached to a
<foreignObject/>. The problem is that these two possible values are not clearly
indicated in the specifications:

http://www.w3.org/TR/SVG11/extend.html#AnExample
http://www.w3.org/TR/XHTMLplusMathMLplusSVG/#howto-xhtml

As a consequence, this use of <switch> to allow alternate content is quite
ironically a problem for interoperability because browsers behave differently:
1) Amaya can display MathML and XHTML inside SVG. It accepts
"http://www.w3.org/1998/Math/MathML" and "http://www.w3.org/1999/xhtml" values.
2) Firefox can display MathML and XHTML inside SVG, but since it refuses
"http://www.w3.org/1998/Math/MathML" and "http://www.w3.org/1999/xhtml" values,
it displays the alternate content.
3) Other browsers that can't render MathML/XHTML in SVG should display the
alternate content.

Can the SVG WG indicates in the spec that browsers able to display MathML and
XHTML inside SVG should recognize the two values
"http://www.w3.org/1998/Math/MathML" and "http://www.w3.org/1999/xhtml"?

Received on Tuesday, 12 August 2008 16:20:34 UTC