From WikiAudio
Below is a working copy-and-past usable piece of code that explains how to connect Web Audio API nodes. It uses an Oscillator Node and a Gain Node.
<!DOCTYPE html > <meta charset="UTF-8"> <title>Test</title>
<button id="soundTrigger" onmousedown = "buzz()">Buzz </button>
<script type="text/javascript">
context = new webkitAudioContext(); // This is the first line of code you always need with the Web Audio API
function buzz(){ // wrap code in function oscillator = context.createOscillator(), // create oscillator oscillator.type = 3; // 4 types of oscillators are available. They are Sine wave = 0, Square wave = 1, Sawtooth wave = 2, Triangle wave = 3, a fourth option exists as well called "custom".
gainNode = context.createGainNode(); // Declare gain node oscillator.connect(gainNode); // Connect sine wave to gain node gainNode.connect(context.destination); // Connect gain node to "speakers" gainNode.gain.value = 1; // This is the volume. oscillator.noteOn(0); // Play sine wave
};
</script>