Trying to record audio in from web browser

Assuming that this is on a PC, you need to select  'stereo mix' as a recording input source in your sound settings panel, and if you are lucky, this will work. It doesn't always, because some manufacturers have been scared by the RIAA into thinking that you could only want to do this for illegal purposes, and consequently they won't let you record anything that streams at all. If this is the case, then there are a few apps around that will bypass all of the rubbish thrown in your path, and let you record directly into them, so you don't have to play about with your 'normal' input settings on Audition. And they'll save a file for you wherever you want it. The one I use is from NCH software and is called SoundTap. It doesn't cost much, and it simply works - no problems at all. I have no connection with them other than as a satisfied customer, incidentally.