Suggest just add css and js to page included mp3 file

The first problem is to know if the page contains an audio file; when the scripts and the CSS files are written on the page the rest of the content is not there and there’s no way to know if the page will include an audio file. Then it’s possible that an audio file is included via ajax on the page and if the scripts are not there the player would never work.
For last all the css and js are cached on the page, after the first time you visit a page they are not loaded from the server anymore but from your cache.

Sorry, I don’t think this is possible.