It appears that the numeric representation of track progress isn't increasing as the song plays! The blue ring works. But, if I click and drag on the ring, the track moves forwards or backwards BUT the track progress doesn't change as I drag. It does change to whatever value its at when I let it go. It then doesn't increment for the rest of the track. If I refresh the window then the progress is displayed but still stays at that same value. Track progress is cleared at the end of the track.
This is on a MacBook Pro with a fully patched Mavericks and standard Safari browser.
Today a coworker brought me his Macbook with Mavericks and Safari up to date, and we replicated the problem. I did a quick test upgrading jQuery Countdown (the plugin we use to display the track progress counter) to the last version and the problem seems to disappear.
Please test it too: go to the plugin's page and download it, then exctract jquery.countdown.js from the .zip archive. Then upload it via SFTP (user: root, passw: rune) in this folder: var/www/js. Let me know if the problem completely disappears.