/*
url-loading object and a request queue built on top of it
*/

/* namespacing object */
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;


/*--- content loader object for cross-browser requests ---*/
net.ContentLoader=function(url,onload, parentParam, onerror,method,params,contentType){

  this.elLoad = document.getElementById("load");
  if (this.elLoad) {
 	this.elLoad.style.visibility = 'visible';
  }
  this.parentParam = parentParam;	
  this.url = url;
  this.method = method;
  this.params = params;
  this.contentType = contentType;
  this.counter = 0;
  this.req=null;
  this.onload=onload;
  this.onerror=(onerror) ? onerror : this.defaultError;
  this.loadXMLDoc(this.url,this.method,this.params,this.contentType);

}

net.ContentLoader.prototype.loadXMLDoc=function(url,method,params,contentType){
  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");
  }
  if (this.req){
    try{
      var loader=this;
      this.req.onreadystatechange=function(){
        net.ContentLoader.onReadyState.call(loader);
      }
      this.req.open(method,url,true);
      if (contentType){
        this.req.setRequestHeader('Content-Type', contentType);
      }
      this.req.send(params);
    }catch (err){
      this.onerror.call(this);
    }
  }
}

net.ContentLoader.prototype.abortXMLDoc=function() {
	if(this.req && this.req.readyState != 4) {
		this.req.abort();
	}
}

net.ContentLoader.onReadyState=function(){
  var req=this.req;
  var ready=req.readyState;
  if (ready==net.READY_STATE_COMPLETE){
	 if (this.elLoad) {
 		this.elLoad.style.visibility = 'hidden';	  
	 }
    var httpStatus=req.status;
    if (httpStatus==200 || httpStatus==0){
	  this.onload.call(this);
    }else{
      // Ñ÷åò÷èê îøèáîê
      this.counter++;
      if (this.counter == 5) {
         this.onerror.call(this);
      }
      else {
        this.loadXMLDoc(this.url,this.method,this.params,this.contentType);
      }
    }
  }
}

net.ContentLoader.prototype.defaultError=function(){
  alert("error fetching data!"
    +"\n\nreadyState:"+this.req.readyState
    +"\nstatus: "+this.req.status
    +"\nheaders: "+this.req.getAllResponseHeaders());
}