Change a Firefox extension script from synchronous to asynchronous

When I submitted the Mozilla Firefox extension 1.4.7 to be reviewed and approved by Mozilla they found something programed in a way that was against their new guidelines and I am looking to see if you can try and fix it. This is what the Mozilla reviewer reported: "(For your next release, please remove the synchronous XMLHttpRequest in login.js. This freezes the UI unnecessarily, specially if the connection is slow.) is not addressed" As you can see, my old programmer must have written a synchronous check on the [login to view URL] and it needs to be asynchronous so that it does not cause any performance issues to the users browser. THE ASK: Can you fix the [login to view URL] part of the extension and make it asynchronous. Then repackage the extension to version 1.4.8?