A common question asked several times about unity post-processing and WebGL, why post-processing is not working on my browser or some of post-processing features are not working in browser: The reason is that post-processing works with WebGL 2 (Unity Forum). Unity WebGL Post processing doesn't work on WebGL1. If your browser and GPU support WebGL 2.0 then PPS (Post Processing stack) should work within your browser. Unity Support graphics API WebGL 1 and WebGL 2 and if Graphic API settings are set to auto then WebGL 2 will try to run first (if supported in the browser) :
