// AJAX client class

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;

net.ContentLoader = function(url, onload, onerror) {
	this.url = url;
	this.req = null;
	this.onload = onload;
	this.onerror = (onerror) ? onerror : this.defaultError;
	this.loadXMLDoc(url);
}

net.ContentLoader.prototype = {
	loadXMLDoc : function(url) {
		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() {
					loader.onReadyState.call(loader);
				}
				this.req.open('GET', url, true);
				this.req.send(null);
			} catch(err) {
				this.onerror.call(this);
			}
		}
	},
	onReadyState : function() {
		var req = this.req;
		var ready = req.readyState;
		if(ready == net.READY_STATE_COMPLETE) {
			var httpStatus = req.status;
			if(httpStatus == 200 || httpStatus == 0) {
				this.onload.call(this);
			} else {
				this.onerror.call(this);
			}
		}
	},
	defaultError : function() {
		alert("error fetching data!" +
			"\n\nreadyState: " + this.req.readyState +
			"\nStatus: " + this.req.status +
			"\nHeaders: " + this.req.getAllResponseHeaders());
	}
}