What's the standard way of dealing with the ordering of multiple ajax requests?

I ended up doing this, which was my original idea:

Code:

(function($){
    var namespace = {
        request_number: 0,
        response_number: 0,
        doTheThing: function(score){
            console.log(score);
        },
        checkServer: function(str) {
            var request_number = funcs.get_request_number();
            $.ajax({
                type: 'post',
                cache: false,
                url: '/check',
                data: {
                    'str': str,
                    'request_number': request_number
                },
                dataType: 'json',
                success: function(response){
                    if(response.score && response.number){
                        var response_number = parseInt(response.number);
                        var response_score = parseInt(response.score);
                        if(response_number > funcs.response_number){
                            funcs.response_number = response_number;
                            funcs.doTheThing(response_score);
                        }
                    }
                }
            });
        },
        get_request_number: function(){
            funcs.request_number++;
            return funcs.request_number;
        }
    };
    window.funcs = ( window.funcs ) ? $.extend( window.funcs, namespace ) : namespace;
})(this.jQuery);

$(document).ready(function(){
    $('#field').on('keyup change blur', function(e){
        var str = $(this).val();
        funcs.checkServer(str);
    });
});

same concept different implimentation.

God Bless CI Contributors