/*

Author Choi jae Hee
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;
  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();
		
		if(this.req.overrideMimeType) {
			this.req.overrideMimeType('text/xml');
		}
	} 
	if (window.ActiveXObject){
		try {
			this.req = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try {
				this.req = new ActiveXObject("Microsoft.XMLHTTP");
			} catch (e) {
				try{
					this.req = new ActiveXObject("window.XMLHttpRequest"); //ie7전용
				}catch(e){}  
			}
		}
		//this.req=new ActiveXObject("Microsoft.XMLHTTP");
	}

	if (this.req){
	
		try{
			var loader=this;
			this.req.open(method,url,true);
			this.req.onreadystatechange=function(){
				net.ContentLoader.onReadyState.call(loader);
			}      
			
			if (contentType){
				this.req.setRequestHeader("Content-Type", contentType);
			}

			this.req.send(params);
		
		}catch (err){
			this.onerror.call(this);
		}
	}
}


net.ContentLoader.onReadyState=function(){
  var req=this.req;
  var ready=req.readyState;
  if (ready==net.READY_STATE_COMPLETE){
    var httpStatus=req.status;
	//alert("text ::" +req.responseText);    
    if (httpStatus==200 || httpStatus==0){
      this.onload.call(this);
    }else{
      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());
}