function HttpClient() { }
HttpClient.prototype = {
// type GET,POST passed to open
requestType:'GET',
// when set to true, async calls are made
isAsync:false,

stat:false,

// where an XMLHttpRequest instance is stored
xmlhttp:false,

// what is called when a successful async call is made
callback:false,

// what is called when send is called on XMLHttpRequest
// set your own function to onSend to have a custom loading
// effect
onSend:function() {
document.getElementById('StatusBar').style.display = 'block';
document.getElementById('StatusBar').innerHTML = '<b>Loading...</b>';
},

// what is called when readyState 4 is reached, this is
// called before your callback
onload:function() {
document.getElementById('StatusBar').style.display ='none';
document.getElementById('StatusBar').innerHTML = '';
},

// what is called when an http error happens
onError:function(error) {
document.getElementById('StatusBar').style.display = 'block';
document.getElementById('StatusBar').innerHTML = error;
},

// method to initialize an xmlhttpclient
init:function() {
   try {
      // Mozilla / Safari
      this.xmlhttp = new XMLHttpRequest();
   }
   catch (e) {
      // IE
      var XMLHTTP_IDS = new Array('MSXML2.XMLHTTP.5.0','MSXML2.XMLHTTP.4.0','MSXML2.XMLHTTP.3.0','MSXML2.XMLHTTP','Microsoft.XMLHTTP');
      var success = false;
      for (var i=0;i < XMLHTTP_IDS.length &&!success; i++) {
         try {
            this.xmlhttp = new ActiveXObject(XMLHTTP_IDS[i]);
            success = true;
         }
         catch (e) {}
      }
      if (!success) { this.onError('Unable to create XMLHttpRequest.'); }
   }
},

// method to make a page request
// @param string url  The page to make the request to
// @param string payload  What you're sending if this is a POST
//                        request
makeRequest: function(url,payload) {
   if (!this.xmlhttp) { this.init(); }
   this.xmlhttp.open(this.requestType,url,this.isAsync);

   // set onreadystatechange here since it will be reset after a
   //completed call in Mozilla
   var self = this;
   this.xmlhttp.onreadystatechange = function() { self._readyStateChangeCallback(url); }
   this.xmlhttp.send(payload);

   if (!this.isAsync) { return this.xmlhttp.responseText; }
},

// internal method used to handle ready state changes
_readyStateChangeCallback:function(url) {
   switch(this.xmlhttp.readyState) {
      case 2:
         this.onSend();
         break;
      case 4:
         this.onload();
         if (this.xmlhttp.status == 200) {
            this.callback(this.xmlhttp.responseText);
           }
         else {
            this.onError('HTTP Error Making Request: '+'['+ this.xmlhttp.status+ ']' + this.xmlhttp.statusText + '<br/>' + url);
         }
         break;
   }
}
}