I have a phonegap app w/ jQuery 1.9.1 Worked great as long as the username doesn\'t have \'@\' symbol in it (like in email addresses). It only fails on iOS.
I suspec
Try wrapping encodeURIComponent() before base64 encoding.
beforeSend: function (xhr) { xhr.setRequestHeader("Authorization", "Basic " + $.base64.encode(encodeURIComponent(this.username + ":" + this.password))); },