Background Audio Cool Trick

I use the following JavaScript to load the music on time line start and later adjust its volume:

//load the scripts dynamically into the head of the document
function add_line() {
var line = document.createElement("audio");
var head=document.getElementsByTagName('body')[0];
line.type = "audio/mp3";
line.src="";
line.id="bgSong" ;
line.autoplay = true;
line.loop = true;
head.appendChild(line);
}

//but we only want to add these once!
if(document.getElementById('bgSong')==null){
add_line();
var audio = document.getElementById('bgSong');
audio.volume = 0.1;
}

//I use a "hidden" web object slide to load my music dynamically. Once I publish the first time, I copy the path to the music file (or files) into a variable titled "location". This is important for the following lines of JavaScript to work.
var player = GetPlayer();
this.Location= player.GetVar("location");
var audio = document.getElementById('bgSong');
audio.src=Location+"Background.mp3";
audio.load();
audio.play();

Then, to adjust the volume, I added 2 buttons (up volume and down volume). The action on the buttons is to adjust a variable (CurrentVolume for example) up or down by increments of 10 as long as it doesn't exceed 100 on the top end or 0 on the bottom.

Next add actions to execute JavaScript if the CurrentVolume variable is equal to each possible volume. 

For example, if current volume variable is adjusted to equal 50, your JavaScript would be the following:
var audio = document.getElementById('bgSong');
audio.volume = 0.5;

This adjusts the volume to 50%