Board Thread:Support Requests - Getting Technical/@comment-5751180-20131115155550/@comment-4018164-20131115163150

Template:MusicPlay in the Club Penguin Wiki does what you're trying to achive. You can find there instructions for how to install it here. But remember that in order to disable it, the viewer must be registered and use his personal pages for disabling the music. It can sometimes be annoying if you already have a music in the background.