function dataURItoBuffer(dataURI){
    var byteString = atob(dataURI.split(',')[1]);
    var buffer = new ArrayBuffer(byteString.length);
    var view = new Uint8Array(buffer);
    for (var i = 0; i < byteString.length; i++) {
        view[i] = byteString.charCodeAt(i);
    }
    return buffer;
}
dataURI to blob, ref to https://gist.github.com/fupslot/5015897
@param dataURI