base64ToBlobURL.js

var base64ToBlobURL = function(base64, cb) {
    base64 = base64.split(',');
    var binary = atob(base64[1]);
    var len = binary.length;
    var buffer = new ArrayBuffer(len);
    var view = new Uint8Array(buffer);
    for (var i = 0; i < len; i++) {
        view[i] = binary.charCodeAt(i);
    }
    var blob = new Blob([view], { type: base64[0].split(':')[1].split(';')[0] });
    return URL.createObjectURL(blob);
};