/* 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.fields = new Array();

    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 && this.method != "POST"){ // TODO: ook bij post laten encoden? probleem met bv een = in een url
                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();
}