jQuery.ajax() method's async option deprecated, what now?

As of jQuery 1.8, the use of async:false in jQuery.ajax() is deprecated.
But how many webpages have you seen with a "loading screen" while there is an ongoing AJAX communication in the background? I have probably seen thousands of them.

My case is that I am writing a mobile app that needs to load a language file. And at the beginning I load the language file and I retrieve the text of the buttons and other GUI elements from the language file.

This is really bad for me. Because if the language file is missing, the GUI shouldn't appear. So how do I solve it? Put all my code in the success callback? That doesn´t seem like a good coding practice to me. Can I solve it another way?

The solution is to manually add an overlay to prevent the user to interact with the interface, and then remove it once the AJAX query is done.

$(function() {
    show_overlay();        

    $.ajax({
        // Query to server
    }).done(function() {
        // Verify good data
        // Do stuff
        remove_overlay();
    });
});

I read the official discussion in the ticket about the deprecation of this parameter and here is what I understood:

• The problem is that implementing Promises (1) for sync AJAX gives them overhead.

• There are tons of real world use cases of sync AJAX, e.g. preserving state before page unload. Therefore, this functionality will stay, but the way you use it may change.

• The nearest solution (landing in 1.8?) is to support only callbacks (but not the Promises) when async is false.

To conclude: Keep using async: false if you have to, but beware of its drawbacks (blocking of VM). Don't worry, you will be provided an alternative if this feature ever gets removed form $.ajax().