一次请求一个ajax

I'm trying

$.ajax({
    // ...,
    async: false,
});

but it doesn't help. There is a way with flag(true/false), but maybe there is more beautiful way how can i do it?

$(window).scroll(function() {
    if ($(window).scrollTop() + $(window).height() > $(document).height() - 220) {
        // ..
        sendRequest();
        // ..
    }
});

This function makes an AJAX request.

In our app we add ajax requests to a queue and then pop them off and execute them one by one. Here is a very simplified version...

var queue = [];

function queueAdd( options ) {

    // ADD AJAX OPTIONS TO QUEUE ARRAY
    queue.push( options );

    // START QUEUE RUNNING
    queueRun();
}

function queueRun() {

    // QUEUE EMPTY OR REQUEST ALREADY ACTIVE
    if ( !queue.length || activeRequest ) return;

    // REMOVE FIRST REQUEST FROM QUEUE
    var request = queue.shift();

    // ATTACH COMPLETE CALLBACK
    request.complete = function( data ) {

        // ACTIVE REQUEST COMPLETED
        activeRequest = false;

        // START NEXT REQUEST IN QUEUE
        queueRun();

        // OPTIONALLY EXECUTE ORIGINAL COMPLETE CALLBACK
        request.complete( data );
    };

    // PREVENT CONCURRENT REQUESTS
    activeRequest = true;

    // EXECUTE AJAX REQUEST
    $.ajax( request );

}