WindowOrWorkerGlobalScope.atob

The WindowOrWorkerGlobalScope.atob() function decodes a string of data which has been encoded using base-64 encoding. You can use the btoa() method to encode and transmit data which may otherwise cause communication problems, then transmit it and use the atob() method to decode the data again. For example, you can encode, transmit, and decode control characters such as ASCII values 0 through 31.

For use with Unicode or UTF-8 strings, see this note at Base64 encoding and decoding and this note at btoa().

Syntax

var decodedData = scope.atob(encodedData);

Throws

Throws a DOMException if encodedData is not valid base64.

Example

var encodedData = window.btoa('Hello, world'); // encode a string
var decodedData = window.atob(encodedData); // decode the string

Specifications

Browser compatibilityUpdate compatibility data on GitHub

See also

• Base64 encoding and decoding
• data URIs
• window.btoa()
• Components.utils.importGlobalProperties