- Styling:
- CSS (close to 100% implementation in IE5.x, NS 6.x, partly in NS 4.x, and 100% in Opera)
- XML display:
- IE5.x (works in NS 6.x and in Opera)
- XSLT:
- Files can be generated off-line with an XSLT processor (eg, saxon, xt, xalan);
IE5.x with beta version of xmlsdk can also perform the transformation on the client side.
- MathML:
- Preview release of IBM's Techexplorer plugin
- SMIL:
- Real Player plugin (there are others, like Oratrix' GRiNS player, Helio Barbizon)
- XHTML+SMIL:
- An early version is part of IE5.5
- SVG:
- Adobe's plugin (there are also separate players from IBM, INRIA, CSIRO, Apache, will be built-in for Mozilla)
The relevant W3C Sites contain up-to-date implementation information!
