read resources form assets folder

[GG-coder889]

how can i read res form assets folder?
when i write the code as below
var audio = new Audio();
audio.src = "audio/bg.mp3";
audio.addEventListener("canplaythrough", function() {
alert('The file is loaded and ready to play!');
}, false);
it comes error:

Unable to read file: file:///android_asset/audio/bg.mp3