Here's my solution

http://pastebin.com/NWc2rWWr

Does what you asked for, it does not cause the browser to hang. Updates the combinations, it won't show every increase in text area, due to the code seemingly going to fast for JS to actually constantly update the text area value, but i added code so the progress shows up in your console, in real time. So if you go to web developer tools, and console, you'll see realtime data.