/*
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,onerror,method,params,contentType){
  this.req=null;
  net.currentLoader=this;
  this.onload=onload;
  this.onerror=(onerror) ? onerror : this.defaultError;
  this.loadXMLDoc(url,method,params,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{
		this.req.onreadystatechange=function(){
			var req=net.currentLoader.req;
			var ready=req.readyState;
			try{var httpStatus=req.status;
				if (ready==net.READY_STATE_COMPLETE){
					if (httpStatus==200 || httpStatus==0){
					    net.currentLoader.onload();
					}else{
						net.currentLoader.onerror();
					}
				}
			}
			catch(err){}					 
		 }

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