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

/* namespacing object */
var ajax=new Object();

ajax.READY_STATE_UNINITIALIZED=0;
ajax.READY_STATE_LOADING=1;
ajax.READY_STATE_LOADED=2;
ajax.READY_STATE_INTERACTIVE=3;
ajax.READY_STATE_COMPLETE=4;

/*--- content loader object for cross-browser requests ---*/
ajax.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);
}

ajax.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) {
		// default
		this.req=new XMLHttpRequest();
	} else if (window.ActiveXObject) {
		try {
			this.req=new ActiveXObject('MSXML2.XMLHTTP.3.0');
		} catch (e1) {
			try {
				this.req=new ActiveXObject("Microsoft.XMLHTTP");
			} catch (e2) {
				// won't work
			}
		}
	}
	
	if (this.req) {
		try{
			var loader=this;
			this.req.onreadystatechange=function() {
				ajax.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);
		}
	}
}


ajax.ContentLoader.onReadyState=function() {
	var req=this.req;
	var ready=req.readyState;
	if (ready==ajax.READY_STATE_COMPLETE) {
		var httpStatus=req.status;
		if (httpStatus==200 || httpStatus==0) {
			this.onload.call(this);
		}else{
			this.onerror.call(this);
		}
	}
}

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