Canvex is believed to work in the following browsers, on any operating system and with no external plugins:

Firefox 1.5+ (2.0 recommended for best performance)

Opera 9

Safari 3

(More details on browser support)

It requires support for a number of existing and experimental standards:

In particular, it will not work (nor get anywhere close to working) in Internet Explorer. It should be able to nearly work in versions of Safari that have SVG support, but that is untested (due to lack of suitable equipment) and will almost certainly reveal bugs.