Firefox 4 and Chrome 9 support 3D graphics in <canvas> through the WebGL API. WebGL is developed by the non-profit Khronos consortium, basically consisting of everybody but Microsoft.
WebGL accesses your hardware driver, giving you hardware acceleration, but also exposing you to a set of vulnerabilities. US CERT now recommends disabling the feature.
To disable WebGL in Firefox, change the preferences:
- navigating to the special about:config URL.
- promise to be careful on the warning page
- type webgl in the filter bar
- toggle the webgl:disabled setting to true