The WindowBase64 helper contains utility methods to convert data to and from base64, a binary-to-text encoding scheme. For example it is used in data URIs.
The WindowBase64.atob() function decodes a string of data which has been encoded using base-64 encoding. You can use the window.btoa() method to encode and transmit data which may otherwise cause communication problems, then transmit it and use the window.atob() method to decode the data again. For example, you can encode, transmit, and decode control characters such as ASCII values 0 through 31.