jQuery AJAX queues

jquery.ajaxqueue.js

/* 
 :: Enhanced Version @extralam ::
 Allows for ajax requests to be run synchronously in a queue , remove queue
 
 Usage::
 var queue = new $.AjaxQueue();

 // add with tag name or not , both ok
 queue.add('test',{
 url: 'url',
 complete: function() {
 console.log('ajax completed');
 },
 _run: function(req) {
 //special pre-processor to alter the request just before it is finally executed in the queue
 req.url = 'changed_url'
 }
 });

 // Cancel Request
 queue.remove('test');

 */

$.AjaxQueue = function() {
    this.reqs = [];
    this.requesting = false;
    this.current_reqs_tag = null;
    this.current_req = null;
};

$.AjaxQueue.prototype = {
    add: function(req) {
        //console.log("Add Request : ");
        this.reqs.push({n : '' , r: req });
        this.next();
    },
    add: function(name , req) {
        console.log("Add Request : " + name);
        this.reqs.push( {n : name , r: req });
        this.next();
    },
    remove: function (name){
        if(this.current_reqs_tag == name){
            console.log("Cancel Request : " + name);
            this.current_req.abort();
            this.current_req = null;
            this.current_reqs_tag = null;
            this.requesting = false;
            this.next();
        }else{
            for (var i = 0; i < this.reqs.length; i++) {
                if(this.reqs[i]['n'] == name){
                    this.reqs.splice(i, 1);
                    break;
                }
            }
        }
    },
    next: function() {
        console.log(' Q Size ' + this.reqs.length);
        if (this.reqs.length == 0) {
            return;
        }

        if (this.requesting == true) {
            return;
        }
        var request = this.reqs.splice(0, 1)[0];
        var req = request['r'];

        var complete = req.complete;
        var self = this;

        self.current_reqs_tag = request['n'];

        if (req._run) {
            req._run(req);
        }
        req.complete = function() {
            if (complete) {
                complete.apply(this, arguments);
            }
            self.requesting = false;
            self.next();
        }

        self.requesting = true;
        self.current_req = $.ajax(req);
    }
};

jquery.ajaxqueue2.js

/* 
 Allows for ajax requests to be run synchronously in a queue
 with pool , without cancel
 Usage::
 var queue = new $.AjaxQueue();

 // add with tag name or not , both ok
 queue.add('test',{
 url: 'url',
 complete: function() {
 console.log('ajax completed');
 },
 _run: function(req) {
 //special pre-processor to alter the request just before it is finally executed in the queue
 req.url = 'changed_url'
 }
 });

 */

$.AjaxQueue = function() {
    this.MAX_POOL_SIZE = 3;
    this.CURR_POOL_SIZE = 0;
    this.reqs = [];
};

$.AjaxQueue.prototype = {
    add: function(req) {
        //console.log("Add Request : ");
        this.reqs.push({n : '' , r: req });
        this.next();
    },
    add: function(name , req) {
        console.log("Add Request : " + name);
        this.reqs.push( {n : name , r: req });
        this.next();
    },
    remove: function (name){
        // TODO: NOT IMPLEMENT
    },
    next: function() {
        console.log(' Q Size ' + this.reqs.length);
        if (this.reqs.length == 0) {
            return;
        }

        if(this.CURR_POOL_SIZE >= this.MAX_POOL_SIZE){
            return;
        }

        var request = this.reqs.splice(0, 1)[0];
        var req = request['r'];

        var complete = req.complete;
        var self = this;

        self.current_reqs_tag = request['n'];

        if (req._run) {
            req._run(req);
        }
        req.complete = function() {
            if (complete) {
                complete.apply(this, arguments);
            }
            self.CURR_POOL_SIZE--;
            self.next();
        }

        self.CURR_POOL_SIZE++;
        self.current_req = $.ajax(req);
    }
};

Can you explain what is "arguments" ? Thank you so much.