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_COMPLETED = 4;

// constructor
net.ContentLoader = function(url, onload, onerror, method, params, contentType)
{
	this.req = null;
	this.url = url;
	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';
		}		
		
		// for mozilla
		if (window.XMLHttpRequest)
		{
			this.req = new XMLHttpRequest();
		}
		// for ie
		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(method, url, true);
				if (contentType)
				{
				    this.req.setRequestHeader('Content-Type', contentType);
				}				
				this.req.send(params);
			}
			catch (err)
			{
				this.onerror.call(this);
			}
		}
	},
	onReadyState: function()
	{
		var req = this.req;
		var ready = req.readyState;
		if (ready == net.READY_STATE_COMPLETED)
		{
			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());
	}
}