Two months ago, I published a jQuery plugin to record audio from browser (without any Media server) called jRecorder
I got many responses and requests to maintain the code with new enhancements and some bug fixes.
Based on that, a new version (1.1) is released which has the capability to preview the recorded audio before sending to the server.
See the example implementation and documentation here.
Also I made this source open and available for anybody to develop at: https://github.com/sythoos/jRecorder/