function AJAXcall(_data, returnFunction) {
    if (!returnFunction) {
        returnFunction = function(){};
    }
    var req = $.ajax({
        url: "ajax?cacheFucker="+Math.random(),
        type: "POST",
        data : _data,
        xhrFields: { withCredentials: true},
        success: function(data, textStatus, jqXHR) {
            returnFunction(data);

            jqXHR.abort();
        },
        error: function (jqXHR, textStatus, errorThrown) {
            returnFunction(false);

            jqXHR.abort();
        }
    });
}

function loadShit() {
    AJAXcall({action:"onlinePlayers"}, function(json) {
        allOnlinePlayers = $.parseJSON(json);
    });
}

setInterval(function() {
    loadShit();
}, 3000);