var net = new Object();
net.READY_STATE_UNINITIALIZED = 0;
net.READY_STATE_LOADING = 1;
net.READY_STATE_LOADED = 2;
net.READY_STATE_INTERACTIVE = 3;
net.READY_STATE_COMPLETE = 4;
net.ContentLoader = function(key, method, url, params, onload, onerror, contentType, headers) {
      this.hashKey = key;
      this.unrequestBrowser = false;
      this.req = null;
      this.onload = onload;
      this.onerror = (onerror) ? onerror : this.defaultError;
      this.loadXMLDoc(method, url, params, contentType, headers);
}
net.ContentLoader.prototype = {
      loadXMLDoc : function(method, url, params, contentType, headers) {
            if (!method) method="GET";
            if (!contentType && method=="POST") contentType='application/x-www-form-urlencoded';
            if (window.XMLHttpRequest) {
                  this.req=new XMLHttpRequest();
            } else if (window.ActiveXObject) {
                  this.req=new ActiveXObject("Microsoft.XMLHTTP");
            } else {
                  this.unrequestBrowser = true;
                  return;
            }
            if (this.req) {
                  try {
                        this.req.open(method,url,true);
                        if (contentType){
                              this.req.setRequestHeader('Content-Type', contentType);
                        }
                        if (headers) {
                              for (var h in headers) {
                                    this.req.setRequestHeader(h,headers[h]);
                              }
                        }
                        var loader=this;
                        this.req.onreadystatechange=function() {
                              loader.onReadyState.call(loader);
                        }
                        this.req.send(params);
                  } catch (err){
                        this.onerror.call(this);
                  }
            }
      },
      onReadyState : function() {
            var req=this.req;
            var ready=req.readyState;
            if (ready==net.READY_STATE_COMPLETE) {
                  var httpStatus=req.status;
                  if (httpStatus==200 || httpStatus==0) {
                        this.onload.call(this);
                  } else {
                        this.onerror.call(this);
                  }
            }
      },
      defaultError : function() {
            alert("error fetching data!"+"\n\nreadyState:"+this.req.readyState +"\nstatus: "+this.req.status+"\nheaders: "+this.req.getAllResponseHeaders());
      }
}
var requestsHash = [];
function setAjaxRequest(method, url, params, onload, onerror, contentType, headers) {
      if (!url) {
            alert("Necessary parameters are not specified");
            return;
      }
      requestsHash.push(new net.ContentLoader(requestsHash.length, method, url, params, onload, onerror, contentType, headers));
      return requestsHash[requestsHash.length - 1].unrequestBrowser;
}