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;

// Constructor
net.CargadorContenidos = function(url, funcion, funcionError) 
{
	this.url = url;
	this.req = null;
	this.onload = funcion;
	this.onerror = (funcionError) ? funcionError : this.defaultError;
	this.cargaContenidoXML(url);
}

net.CargadorContenidos.prototype = 
{
	cargaContenidoXML: 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("Se ha producido un error al obtener los datos"
		+ "\n\nreadyState:" + this.req.readyState
		+ "\nstatus: " + this.req.status
		+ "\nheaders: " + this.req.getAllResponseHeaders());
	}
}