Asm.js in Firefox Nightly
Actual numbers from the Groups link at the bottom:    So I discovered from Alan today - asm.js was everything I hoped it would
    be. 

    One of the more intensive examples in OpenSCAD
    (https://raw.github.com/openscad/openscad/master/examples/example006.scad)
    gave me these metrics:

    Native: 402 seconds, 
    asm.js version: 605 seconds, 
    asm.js version in Chrome: 3724 seconds


And the exciting part? Backwards compatibility even with IE6, forwards compatibility with optimizations that haven't been invented yet – and no 80s era blob+VM architecture in sight. All without inventing any half baked new language, file format, virtual machines or whatever else, and building on a language spec that's already an ISO standard. Eat your heart out Native Client!