Canvas to webkit url without crashing your browser see references : https://code.google.com/p/chromium/issues/detail?id=69227

getCanvasUrl.js

function getCanvasURL(canvas){
  var parts = canvas.toDataURL().match(/data:([^;]*)(;base64)?,([0-9A-Za-z+/]+)/);

  //assume base64 encoding
  var binStr = atob(parts[3]);

  //convert to binary in ArrayBuffer
  var buf = new ArrayBuffer(binStr.length);
  var view = new Uint8Array(buf);
  for (var i = 0; i < view.length; i++)
    view[i] = binStr.charCodeAt(i);

  var blob = new Blob([view], {
    'type': parts[1]
  });
  return webkitURL.createObjectURL(blob);
}