function sack(file) {
    this.xmlhttp = null;
    this.resetData = function () {
        this.method = "POST";
        this.queryStringSeparator = "?";
        this.argumentSeparator = "&";
        this.URLString = "";
        this.encodeURIString = true;
        this.execute = false;
        this.element = null;
        this.elementObj = null;
        this.requestFile = file;
        this.vars = new Object();
        this.responseStatus = new Array(2);
    };
    this.resetFunctions = function () {
        this.onLoading = function () {};
        this.onLoaded = function () {};
        this.onInteractive = function () {};
        this.onCompletion = function () {};
        this.onError = function () {};
        this.onFail = function () {};
    };
    this.reset = function () {
        this.resetFunctions();
        this.resetData();
    };
    this.createAJAX = function () {
        if (typeof XMLHttpRequest != "undefined") this.xmlhttp = new XMLHttpRequest();

        if (!this.xmlhttp) {
            try {
                this.xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
            } catch(e1) {
                try {
                    this.xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
                } catch(e2) {
                    this.xmlhttp = null;
                    this.failed = true;
                }
            }
        }
    };

    this.setVar = function (name, value) {
        this.vars[name] = Array(value, false);
    };
    this.encVar = function (name, value, returnvars) {
        if (true == returnvars) {
            return Array(encodeURIComponent(name), encodeURIComponent(value));
        } else {
            this.vars[encodeURIComponent(name)] = Array(encodeURIComponent(value), true);
        }
    };
    this.processURLString = function (string, encode) {
        encoded = encodeURIComponent(this.argumentSeparator);
        regexp = new RegExp(this.argumentSeparator + "|" + encoded);
        varArray = string.split(regexp);
        for (i = 0; i < varArray.length; i++) {
            urlVars = varArray[i].split("=");
            if (true == encode) {
                this.encVar(urlVars[0], urlVars[1]);
            } else {
                this.setVar(urlVars[0], urlVars[1]);
            }
        }
    };
    this.createURLString = function (urlstring) {
        if (this.encodeURIString && this.URLString.length) {
            this.processURLString(this.URLString, true);
        }
        if (urlstring) {
            if (this.URLString.length) {
                this.URLString += this.argumentSeparator + urlstring;
            } else {
                this.URLString = urlstring;
            }
        }
        this.setVar("rndval", new Date().getTime());
        urlstringtemp = new Array();
        for (key in this.vars) {
            if (false == this.vars[key][1] && true == this.encodeURIString) {
                encoded = this.encVar(key, this.vars[key][0], true);
                delete this.vars[key];
                this.vars[encoded[0]] = Array(encoded[1], true);
                key = encoded[0];
            }
            urlstringtemp[urlstringtemp.length] = key + "=" + this.vars[key][0];
        }
        if (urlstring) {
            this.URLString += this.argumentSeparator + urlstringtemp.join(this.argumentSeparator);
        } else {
            this.URLString += urlstringtemp.join(this.argumentSeparator);
        }
    };
    this.runResponse = function () {
        eval(this.response);
    };
    this.runAJAX = function (urlstring) {
        if (this.failed) {
            this.onFail();
        } else {
            this.createURLString(urlstring);
            if (this.element) {
                this.elementObj = document.getElementById(this.element);
            }
            if (this.xmlhttp) {
                var self = this;
                if (this.method == "GET") {
                    totalurlstring = this.requestFile + this.queryStringSeparator + this.URLString;
                    this.xmlhttp.open(this.method, totalurlstring, true);
                } else {
                    this.xmlhttp.open(this.method, this.requestFile, true);
                    try {
                        this.xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
                    } catch(e) {}
                }
                this.xmlhttp.onreadystatechange = function () {
                    switch (self.xmlhttp.readyState) {
                    case 1:
                        self.onLoading();
                        break;
                    case 2:
                        self.onLoaded();
                        break;
                    case 3:
                        self.onInteractive();
                        break;
                    case 4:
                        self.response = self.xmlhttp.responseText;
                        self.responseXML = self.xmlhttp.responseXML;
                        self.responseStatus[0] = self.xmlhttp.status;
                        self.responseStatus[1] = self.xmlhttp.statusText;
                        if (self.execute) {
                            self.runResponse();
                        }
                        if (self.elementObj) {
                            elemNodeName = self.elementObj.nodeName;
                            elemNodeName.toLowerCase();
                            if (elemNodeName == "input" || elemNodeName == "select" || elemNodeName == "option" || elemNodeName == "textarea") {
                                self.elementObj.value = self.response;
                            } else {
                                self.elementObj.innerHTML = self.response;
                            }
                        }
                        if (self.responseStatus[0] == "200") {
                            self.onCompletion();
                        } else {
                            self.onError();
                        }
                        self.URLString = "";
                        break
                    }
                };
                this.xmlhttp.send(this.URLString);
            }
        }
    };
    this.reset();
    this.createAJAX();
}