Works great. The extension Stop Autoplay conflicts with it but I ended up uninstalling that extension anyways.
I used to use the Google version of this script, but have now switched to the JW version. JW version looks nicer and provides better functionality.
All that would make this script better (all versions) would be the possibility of instead adding an inline button to the page, which when clicked would load the inline mp3 player in its place. On pages with a lot of mp3 links, the current setup can slow down page loading.
The MP3 player (JW) is smaller than Google's. That's why I prefer this one.
It would be the best if it can implement a nice feature from WordPress version.
WordPress MP3 player only expands when you click to play. It's very nice to the page where there are many MP3 links.