Question

Is it possible to access the username (and optionally password), currently used for HTTP authentication from Javascript code on the page?

Answer 1

Edit: In this answer I explain how to access a page or service via ajax that requires basic http authentication.

If you mean basic http authentication, then it should be possible (I have never tried it myself).

Basic authentication means that you add the http header Authorization to your request, and the XmlHttpRequest object supports adding custom headers with the method setRequestHeader().

The http header looks like this:

Authorization: Basic {authentication token}

where the authentication token is constructed like this:

authentication token := base64(username + ":" + password)

Javascript doesn’t have standard functions to encode to Base64, but this SO question shows you how to do that.