wiki.webvm.net/ webvm/ Requirements

For WebVM to be work the end user needs

The WebVM plugin and a browser that supports the scriptable NPAPI plugin interface. For example:

webvm will probably be installed with Aplix’s help on zillions of JBlend mobile device deployments.

If you are a browser vendor, you can use our NPAPI test plugin to ensure your browser supports WebVM.

Also see development progress with respect to npapi compatibility between platforms.