simple button to download an mp3 from youtube
scriptish button
Click the 'plus' button to make the link appear.
If the video has already been processed by YoutubeInMp3, the link immediately starts a download. Else it leads to a page where you have to click "convert and download" to get the file. Hence I recommend middle-clicking on it to be sure it won't quit your video.
I made this for myself, the code is as simple as possible so you should not have any performance/compatibility issue. If you have any issue, please post a feedback (it's easy you don't even have to create a account if you sign in through google)
uses youtubeinmp3.com api http://youtubeinmp3.com/api/
