I'm using the [JavaScript SDK by Stack Exchange][1] provided with the latest API, and despite following the official instructions & examples it doesn't work - it seems there is a bug which breaks the workflow, and I believe it's on Stack Exchange's side. The issue is that `https://stackexchange.com/oauth/login_success` never gets information about success/error of the authorization workflow, it just stays on the "Authorizing Application" step, never going further. Further investigations show a Chrome Console output showing us a `Uncaught TypeError: Cannot read property 'msie' of undefined` jQuery error on Stack Exchange's login_success page: login_success?assisted=8723&protocol=https&proxy=https://zendesk.mvink.me/integrations/stackexchang…:122 Uncaught TypeError: Cannot read property 'msie' of undefined at HTMLDocument.<anonymous> (login_success?assisted=8723&protocol=https&proxy=https://zendesk.mvink.me/integrations/stackexchang…:122) at i (jquery.min.js:2) at Object.fireWith [as resolveWith] (jquery.min.js:2) at Function.ready (jquery.min.js:2) at HTMLDocument.K (jquery.min.js:2) (anonymous) @ login_success?assisted=8723&protocol=https&proxy=https://zendesk.mvink.me/integrations/stackexchang…:122 i @ jquery.min.js:2 fireWith @ jquery.min.js:2 ready @ jquery.min.js:2 K @ jquery.min.js:2 Looking into the source code, it seems you are using `$.browser.msie && $.browser.version` which [has been deprecated in jQuery 1.9][2], and you are currently using jQuery 1.12 on this page. // IE technically supports postMessage, but does a *really* bad job of it if (window.postMessage && !($.browser.msie && $.browser.version <= '9.0')) { // modern browsers window.opener.postMessage(window.location.hash, 'https://zendesk.mvink.me'); } else { The result is - success action is never passed to the host window (the one auth process has been called from), so it's not possible to get an access token back. Please have a look into this. [1]: https://api.stackexchange.com/docs/js-lib [2]: http://jquery.com/upgrade-guide/1.9/#jquery-browser-removed