/* Simple AJAX Code-Kit (SACK) */
/* ©2005 Gregory Wild-Smith */
/* www.twilightuniverse.com */
/* Software licenced under a modified X11 licence, see documentation or authors website for more details */

function sack(file){
        this.AjaxFailedAlert = "Your browser does not support the enhanced functionality of this website, and therefore you will have an experience that differs from the intended one.\n";
        this.requestFile = file;
        this.method = "POST";
        this.URLString = "";
        this.encodeURIString = true;
        this.execute = false;

        this.onLoading = function() { };
        this.onLoaded = function() { };
        this.onInteractive = function() { };
        this.onCompletion = function() { };

        this.createAJAX = function() {
                try {
                        this.xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
                } catch (e) {
                        try {
                                this.xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
                        } catch (err) {
                                this.xmlhttp = null;
                        }
                }
                if(!this.xmlhttp && typeof XMLHttpRequest != "undefined")
                        this.xmlhttp = new XMLHttpRequest();
                if (!this.xmlhttp){
                        this.failed = true;
                }
        };

        this.setVar = function(name, value){
                if (this.URLString.length < 3){
                        this.URLString = name + "=" + value;
                } else {
                        this.URLString += "&" + name + "=" + value;
                }
        }

        this.encVar = function(name, value){
                var varString = encodeURIComponent(name) + "=" + encodeURIComponent(value);
        return varString;
        }

        this.encodeURLString = function(string){
                varArray = string.split('&');
                for (i = 0; i < varArray.length; i++){
                        urlVars = varArray[i].split('=');
                        if (urlVars[0].indexOf('amp;') != -1){
                                urlVars[0] = urlVars[0].substring(4);
                        }
                        varArray[i] = this.encVar(urlVars[0],urlVars[1]);
                }
        return varArray.join('&');
        }

        this.runResponse = function(){
                eval(this.response);
        }

        this.runAJAX = function(urlstring){
                this.responseStatus = new Array(2);
                if(this.failed && this.AjaxFailedAlert){
                        alert(this.AjaxFailedAlert);
                } else {
                        if (urlstring){
                                if (this.URLString.length){
                                        this.URLString = this.URLString + "&" + urlstring;
                                } else {
                                        this.URLString = urlstring;
                                }
                        }
                        if (this.encodeURIString){
                                var timeval = new Date().getTime();
                                this.URLString = this.encodeURLString(this.URLString);
                                this.setVar("rndval", timeval);
                        }
                        if (this.element) { this.elementObj = document.getElementById(this.element); }
                        if (this.xmlhttp) {
                                var self = this;
                                if (this.method == "GET") {
                                        var totalurlstring = this.requestFile + "?" + this.URLString;
                                        this.xmlhttp.open(this.method, totalurlstring, true);
                                } else {
                                        this.xmlhttp.open(this.method, this.requestFile, true);
                                }
                                if (this.method == "POST"){
                                          try {
                                                this.xmlhttp.setRequestHeader('Content-Type','application/x-www-form-urlencoded')
                                        } catch (e) {}
                                }

                                this.xmlhttp.send(this.URLString);
                                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;
                                                        self.onCompletion();
                                                        if(self.execute){ self.runResponse(); }
                                                        if (self.elementObj) {
                                                                var 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;
                                                                }
                                                        }
                                                        self.URLString = "";
                                                break;
                                        }
                                };
                        }
                }
        };
        this.createAJAX();
}