Stream recorded audio from browser to server
I'm doing this currently with some software that allows for streaming to internet radio servers via your web browser.
I use the WebAudio API along with getUserMedia to get live PCM audio data from the sound device. From there, I convert this data from 32-bit float to 16, 12, or 8 bit data depending on the amount of bandwidth available. This converted int samples are written to a stream setup with BinaryJS which wraps streams on both the Node.js and the client. As a bonus with BinaryJS, you can have as many streams open as you want, so I use a second stream over the same WebSocket connection for control data.