Capture audio and write audio file from a webgl build (need to be in game feature)

Hey,

I'm making a interactive clip for a very cool music group.

We would like to give the possibility to the player to export the audio file from his playthrough. (as it will be different from a player to another)

I have been searching for that and what I found was just "use audacity or else" which is not possible in my case, we want this to be a + cool feature for the player.

I just would like to know if it's possible, in webgl, or, with a classic pc/mac build.

Thanks in advance for you precious help and time,

Jonathan