/* Simple AJAX Code-Kit (SACK) v1.6.1 */
/* ©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.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() {
            var aVersions = [ "MSXML2.XMLHttp.5.0",
                "MSXML2.XMLHttp.4.0","MSXML2.XMLHttp.3.0",
                "MSXML2.XMLHttp","Microsoft.XMLHttp"
            ];

            for (var i = 0; (i < aVersions.length) && (!this.xmlhttp); i++) {
                try {
                    this.xmlhttp = new ActiveXObject(aVersions[i]);
                } catch (oError) {
                    //Do nothing
                }
            }
            if (! this.xmlhttp) {
                  if (typeof XMLHttpRequest != "undefined") {
                        this.xmlhttp = new XMLHttpRequest();
                  } else {
                        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;
                  }
            }

            // prevents caching of 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();
}