window.btoa and window.atob tests

Created for testing window.btoa and window.atob, with and without a polyfill.

HTML

<div id=testDiv></div>

<image id=testImg></image>

JavaScript

function b64toBlob(b64Data, contentType, sliceSize) {

    contentType = contentType || '';

    sliceSize = sliceSize || 512;

    var byteCharacters = atob(b64Data);

    var byteArrays = [];

    for (var offset = 0; offset < byteCharacters.length; offset += sliceSize) {

        var slice = byteCharacters.slice(offset, offset + sliceSize);

        var byteNumbers = new Array(slice.length);

        for (var i = 0; i < slice.length; i++) {

            byteNumbers[i] = slice.charCodeAt(i);

        }

        var byteArray = new Uint8Array(byteNumbers);

        byteArrays.push(byteArray);

    }

    var blob = new Blob(byteArrays, {type: contentType});

    return blob;

}

var inputBase64 =...