Ajax = {
        request : function(method, uri, cb, data, options) {
            if(options){
                var hs = options.headers;
                if(hs){
                    for(var h in hs){
                        if(hs.hasOwnProperty(h)){
                            this.initHeader(h, hs[h], false);
                        }
                    }
                }
                if(options.xmlData){
                    this.initHeader('Content-Type', 'text/xml', false);
                    method = 'POST';
                    data = options.xmlData;
                }else if(options.jsonData){
                    this.initHeader('Content-Type', 'text/javascript', false);
                    method = 'POST';
                    data = typeof options.jsonData == 'object' ? Ext.encode(options.jsonData) : options.jsonData;
                }
            }

            return this.asyncRequest(method, uri, cb, data);
        },

        serializeForm : function(form) {
            if(typeof form == 'string') {
                form = (document.getElementById(form) || document.forms[form]);
            }

            var el, name, val, disabled, data = '', hasSubmit = false;
            for (var i = 0; i < form.elements.length; i++) {
                el = form.elements[i];
                disabled = form.elements[i].disabled;
                name = form.elements[i].name;
                val = form.elements[i].value;

                if (!disabled && name){
                    switch (el.type)
                            {
                        case 'select-one':
                        case 'select-multiple':
                            for (var j = 0; j < el.options.length; j++) {
                                if (el.options[j].selected) {
                                    if (Ext.isIE) {
                                        data += encodeURIComponent(name) + '=' + encodeURIComponent(el.options[j].attributes['value'].specified ? el.options[j].value : el.options[j].text) + '&';
                                    }
                                    else {
                                        data += encodeURIComponent(name) + '=' + encodeURIComponent(el.options[j].hasAttribute('value') ? el.options[j].value : el.options[j].text) + '&';
                                    }
                                }
                            }
                            break;
                        case 'radio':
                        case 'checkbox':
                            if (el.checked) {
                                data += encodeURIComponent(name) + '=' + encodeURIComponent(val) + '&';
                            }
                            break;
                        case 'file':

                        case undefined:

                        case 'reset':

                        case 'button':

                            break;
                        case 'submit':
                            if(hasSubmit == false) {
                                data += encodeURIComponent(name) + '=' + encodeURIComponent(val) + '&';
                                hasSubmit = true;
                            }
                            break;
                        default:
                            data += encodeURIComponent(name) + '=' + encodeURIComponent(val) + '&';
                            break;
                    }
                }
            }
            data = data.substr(0, data.length - 1);
            return data;
        },

        headers:{},

        hasHeaders:false,

        useDefaultHeader:true,

        defaultPostHeader:'application/x-www-form-urlencoded',

        useDefaultXhrHeader:true,

        defaultXhrHeader:'XMLHttpRequest',

        hasDefaultHeaders:true,

        defaultHeaders:{},

        poll:{},

        timeout:{},

        pollInterval:50,

        transactionId:0,

        setProgId:function(id)
        {
            this.activeX.unshift(id);
        },

        setDefaultPostHeader:function(b)
        {
            this.useDefaultHeader = b;
        },

        setDefaultXhrHeader:function(b)
        {
            this.useDefaultXhrHeader = b;
        },

        setPollingInterval:function(i)
        {
            if (typeof i == 'number' && isFinite(i)) {
                this.pollInterval = i;
            }
        },

        createXhrObject:function(transactionId)
        {
            var obj,http;
            try
            {

                http = new XMLHttpRequest();

                obj = { conn:http, tId:transactionId };
            }
            catch(e)
            {
                for (var i = 0; i < this.activeX.length; ++i) {
                    try
                    {

                        http = new ActiveXObject(this.activeX[i]);

                        obj = { conn:http, tId:transactionId };
                        break;
                    }
                    catch(e) {
                    }
                }
            }
            finally
            {
                return obj;
            }
        },

        getConnectionObject:function()
        {
            var o;
            var tId = this.transactionId;

            try
            {
                o = this.createXhrObject(tId);
                if (o) {
                    this.transactionId++;
                }
            }
            catch(e) {
            }
            finally
            {
                return o;
            }
        },

        asyncRequest:function(method, uri, callback, postData)
        {
            var o = this.getConnectionObject();

            if (!o) {
                return null;
            }
            else {
                o.conn.open(method, uri, true);

                if (this.useDefaultXhrHeader) {
                    if (!this.defaultHeaders['X-Requested-With']) {
                        this.initHeader('X-Requested-With', this.defaultXhrHeader, true);
                    }
                }

                if(postData && this.useDefaultHeader){
                    this.initHeader('Content-Type', this.defaultPostHeader);
                }

                 if (this.hasDefaultHeaders || this.hasHeaders) {
                    this.setHeader(o);
                }

                this.handleReadyState(o, callback);
                o.conn.send(postData || null);

                return o;
            }
        },

        handleReadyState:function(o, callback)
        {
            var oConn = this;

            if (callback && callback.timeout) {
                this.timeout[o.tId] = window.setTimeout(function() {
                    oConn.abort(o, callback, true);
                }, callback.timeout);
            }

            this.poll[o.tId] = window.setInterval(
                    function() {
                        if (o.conn && o.conn.readyState == 4) {
                            window.clearInterval(oConn.poll[o.tId]);
                            delete oConn.poll[o.tId];

                            if (callback && callback.timeout) {
                                window.clearTimeout(oConn.timeout[o.tId]);
                                delete oConn.timeout[o.tId];
                            }

                            oConn.handleTransactionResponse(o, callback);
                        }
                    }
                    , this.pollInterval);
        },

        handleTransactionResponse:function(o, callback, isAbort)
        {

            if (!callback) {
                this.releaseObject(o);
                return;
            }

            var httpStatus, responseObject;

            try
            {
                if (o.conn.status !== undefined && o.conn.status != 0) {
                    httpStatus = o.conn.status;
                }
                else {
                    httpStatus = 13030;
                }
            }
            catch(e) {


                httpStatus = 13030;
            }

            if (httpStatus >= 200 && httpStatus < 300) {
                responseObject = this.createResponseObject(o, callback.argument);
                if (callback.success) {
                    if (!callback.scope) {
                        callback.success(responseObject);
                    }
                    else {


                        callback.success.apply(callback.scope, [responseObject]);
                    }
                }
            }
            else {
                switch (httpStatus) {

                    case 12002:
                    case 12029:
                    case 12030:
                    case 12031:
                    case 12152:
                    case 13030:
                        responseObject = this.createExceptionObject(o.tId, callback.argument, (isAbort ? isAbort : false));
                        if (callback.failure) {
                            if (!callback.scope) {
                                callback.failure(responseObject);
                            }
                            else {
                                callback.failure.apply(callback.scope, [responseObject]);
                            }
                        }
                        break;
                    default:
                        responseObject = this.createResponseObject(o, callback.argument);
                        if (callback.failure) {
                            if (!callback.scope) {
                                callback.failure(responseObject);
                            }
                            else {
                                callback.failure.apply(callback.scope, [responseObject]);
                            }
                        }
                }
            }

            this.releaseObject(o);
            responseObject = null;
        },

        createResponseObject:function(o, callbackArg)
        {
            var obj = {};
            var headerObj = {};

            try
            {
                var headerStr = o.conn.getAllResponseHeaders();
                var header = headerStr.split('\n');
                for (var i = 0; i < header.length; i++) {
                    var delimitPos = header[i].indexOf(':');
                    if (delimitPos != -1) {
                        headerObj[header[i].substring(0, delimitPos)] = header[i].substring(delimitPos + 2);
                    }
                }
            }
            catch(e) {
            }

            obj.tId = o.tId;
            obj.status = o.conn.status;
            obj.statusText = o.conn.statusText;
            obj.getResponseHeader = headerObj;
            obj.getAllResponseHeaders = headerStr;
            obj.responseText = o.conn.responseText;
            obj.responseXML = o.conn.responseXML;

            if (typeof callbackArg !== undefined) {
                obj.argument = callbackArg;
            }

            return obj;
        },

        createExceptionObject:function(tId, callbackArg, isAbort)
        {
            var COMM_CODE = 0;
            var COMM_ERROR = 'communication failure';
            var ABORT_CODE = -1;
            var ABORT_ERROR = 'transaction aborted';

            var obj = {};

            obj.tId = tId;
            if (isAbort) {
                obj.status = ABORT_CODE;
                obj.statusText = ABORT_ERROR;
            }
            else {
                obj.status = COMM_CODE;
                obj.statusText = COMM_ERROR;
            }

            if (callbackArg) {
                obj.argument = callbackArg;
            }

            return obj;
        },

        initHeader:function(label, value, isDefault)
        {
            var headerObj = (isDefault) ? this.defaultHeaders : this.headers;

            if (headerObj[label] === undefined) {
                headerObj[label] = value;
            }
            else {


                headerObj[label] = value + "," + headerObj[label];
            }

            if (isDefault) {
                this.hasDefaultHeaders = true;
            }
            else {
                this.hasHeaders = true;
            }
        },


        setHeader:function(o)
        {
            if (this.hasDefaultHeaders) {
                for (var prop in this.defaultHeaders) {
                    if (this.defaultHeaders.hasOwnProperty(prop)) {
                        o.conn.setRequestHeader(prop, this.defaultHeaders[prop]);
                    }
                }
            }

            if (this.hasHeaders) {
                for (var prop in this.headers) {
                    if (this.headers.hasOwnProperty(prop)) {
                        o.conn.setRequestHeader(prop, this.headers[prop]);
                    }
                }
                this.headers = {};
                this.hasHeaders = false;
            }
        },

        resetDefaultHeaders:function() {
            delete this.defaultHeaders;
            this.defaultHeaders = {};
            this.hasDefaultHeaders = false;
        },

        abort:function(o, callback, isTimeout)
        {
            if (this.isCallInProgress(o)) {
                o.conn.abort();
                window.clearInterval(this.poll[o.tId]);
                delete this.poll[o.tId];
                if (isTimeout) {
                    delete this.timeout[o.tId];
                }

                this.handleTransactionResponse(o, callback, true);

                return true;
            }
            else {
                return false;
            }
        },


        isCallInProgress:function(o)
        {


            if (o.conn) {
                return o.conn.readyState != 4 && o.conn.readyState != 0;
            }
            else {

                return false;
            }
        },


        releaseObject:function(o)
        {

            o.conn = null;

            o = null;
        },

        activeX:[
        'MSXML2.XMLHTTP.3.0',
        'MSXML2.XMLHTTP',
        'Microsoft.XMLHTTP'
        ]


    };


    /**
    * The queue that will store all XMLHttpRequests
    */
    Ext.lib.Ajax._queue = [];

    /**
    * Stores the number of XMLHttpRequests being processed
    */
    Ext.lib.Ajax._activeRequests = 0;

    /**
    * Overwritten so pending XMLHttpRequests in the queue will be removed 
    */
    Ext.lib.Ajax.abort = function(o, callback, isTimeout) {
        if (this.isCallInProgress(o)) {
            o.conn.abort();
            window.clearInterval(this.poll[o.tId]);
            delete this.poll[o.tId];
            if (isTimeout) {
                delete this.timeout[o.tId];
            }

            this.handleTransactionResponse(o, callback, true);

            return true;
        }
        else {

            // check if the connection is pending and delete it
            for (var i = 0, max_i = this._queue.length; i < max_i; i++) {
                if (this._queue[i].o.tId == o.tId) {
                    this._queue.splice(i, 1);
                    break;
                }
            }

            return false;
        }
    };

    /**
    * Pushes the XMLHttpRequests into the queue and processes the queue afterwards.
    *
    */
    Ext.lib.Ajax.asyncRequest = function(method, uri, callback, postData) {
        var o = this.getConnectionObject();

        if (!o) {
            return null;
        }
        else {

            this._queue.push({
                o: o,
                method: method,
                uri: uri,
                callback: callback,
                postData: postData
            });

            this._processQueue();

            return o;
        }
    };

    /**
    * Peeks into the queue and will process the first XMLHttpRequest found, if, and only if
    * there are not more than 2 simultaneously XMLHttpRequests already processing.
    */
    Ext.lib.Ajax._processQueue = function() {
        var to = this._queue[0];

        if (to && this._activeRequests < 1) {
            to = this._queue.shift();
            this._asyncRequest(to.o, to.method, to.uri, to.callback, to.postData);
        }

    };

    /**
    * Executes a XMLHttpRequest and updates the _activeRequests property to match the
    * number of concurrent ajax calls.
    */
    Ext.lib.Ajax._asyncRequest = function(o, method, uri, callback, postData) {
        this._activeRequests++;
        o.conn.open(method, uri, true);

        if (this.useDefaultXhrHeader) {
            if (!this.defaultHeaders['X-Requested-With']) {
                this.initHeader('X-Requested-With', this.defaultXhrHeader, true);
            }
        }

        if (postData && this.useDefaultHeader) {
            this.initHeader('Content-Type', this.defaultPostHeader);
        }

        if (this.hasDefaultHeaders || this.hasHeaders) {
            this.setHeader(o);
        }

        this.handleReadyState(o, callback);
        o.conn.send(postData || null);

    };

    /**
    * Called after a XMLHttpRequest finishes. Updates the number of ongoing ajax calls
    * and checks afterwards if there are still requests pending.
    */
    Ext.lib.Ajax.releaseObject = function(o) {
        o.conn = null;
        o = null;

        this._activeRequests--;
        this._processQueue();
    };