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

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

	 statusDiv:'HttpClientStatus',
     // 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(this.statusDiv).style.display = 'block';
     },
	 
     // what is called when readyState 4 is reached, this is
     // called before your callback
      onload:function() {
      //    document.getElementById(this.statusDiv).style.display = 'none';
      },
	  // what is called when an http error happens
     onError:function(error) {
         alert(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);
		 this.xmlhttp.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');

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

         this.xmlhttp.send(payload);

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

     // internal method used to handle ready state changes
    _readyStateChangeCallback:function() {
		 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);
               }
               break;
         }
     }
 }