A quick evaluation of some FFT jobs in Javascript.
Packaged Javascript versions of the benchmarked FFTW and KissFFT modules are available.
Running in Chrome 62 on OSX
Uses existing library code where possible, and compares "Javascript source" with code compiled from other languages using Emscripten or similar. Only forward transforms are tested at this point (the inverse transforms may or may not produce the right results).
You can run these tests in a browser by checking out this repo and opening the file fft/index.html.
Since the fork we've added a modified version of the DSP.js FFT and a Real-to-Real algorithm from FFTW. As well as an optimization to the compile parameters which vastly improved the runtime of both FFTW and KissFFT ports. You can view the original Mercurial repository by Chris Cannam (from which this is forked) here.