var xhr = new XMLHttpRequest();
xhr.open('GET', 'song.mp3', true);
xhr.responseType = 'arraybuffer';
xhr.onload = function()
{
audioContext.decodeAudioData(
xhr.response,
function(buffer)
{
var c = document.getElementById('canvas-view1');
drawBuffer(c.width, c.height, c.getContext('2d'), buffer)
})
}
xhr.send()