I am making a game with HTML5 and JavaScript.
How could I play game audio via JavaScript?
It's easy, just get your audio element and call the play() method:
document.getElementById('yourAudioTag').play();
Check out this example: http://www.storiesinflight.com/html5/audio.html
This site uncovers some of the other cool things you can do such as load(), pause(), and a few other properties of the audio element.