Description
MDN URL
https://developer.mozilla.org/en-US/docs/Web/API/Window/atob
What specific section or headline is this issue about?
No response
What information was incorrect, unhelpful, or incomplete?
Return value
An ASCII string containing decoded data from encodedData.
An ASCII string containing decoded data from encodedData.
In the mdn article is mentioned, that the atob function would return an ASCII string ( a series of ASCII characters). ASCII is 7bit. The base 64 encoded data contains byte values from 0 to 255. That doesnt suit. Extended ASCII would contain values from 0 to 255 according to what map, Windows-1252 ,...?
The string characters of Javascript are 16 bit UTF-16 values. if it would return an Extented ASCII string,, the byte values has to be readed according a map like windows-1252, and then the characters need to be converted to unicode codepoints to save it as an Javascript UTF16 string!
Thats not the case.
What the function returns is a unicode string, which contains a series of unicode characters from unicode codepoint 0 to 255. So each character represents a two byte (16 bit) value, with values from( 0 to 255). You can get the value witch .charCodeAt(x).!
What did you expect to see?
Return value
An Unicode string containing the decoded data from encodedData as series of unicode chars from codepoint 0 to 255.
Do you have any supporting links, references, or citations?
No response
Do you have anything more you want to share?
No response
MDN metadata
Page report details
- Folder:
en-us/web/api/window/atob - MDN URL: https://developer.mozilla.org/en-US/docs/Web/API/Window/atob
- GitHub URL: https://github.com/mdn/content/blob/main/files/en-us/web/api/window/atob/index.md
- Last commit: 4d9320f
- Document last modified: 2025-02-18T11:44:37.000Z