Request.XDR.js

if (window.XDomainRequest) (function(){

var onLoad = function(){
	cleanup(this.xhr);
	this.response = {text: this.xhr.responseText, xml: this.xhr.responseXML};
	this.success(this.response.text, this.response.xml);
};

var onError = function(){
	cleanup(this.xhr);
	this.response = {text: null, xml: null};
	this.failure();
};

var cleanup = function(xhr){
	if (this.xhr.onload) this.xhr.onload = this.xhr.onerror = this.xhr.ontimeout = function(){};
};

Class.refactor(Request, {

	openRequest: function(method, url, data, xd){
		if (xd && this.options.async){
			this.xhr = new XDomainRequest();
			this.xhr.open(method.toUpperCase(), url);
			this.xhr.onload = onLoad.bind(this);
			this.xhr.onerror = this.xhr.ontimeout = onError.bind(this);
			this.fireEvent('request');
			this.xhr.send(data);
			return this;
		}
		return this.previous.apply(this, arguments);
	},

	getHeader: function(name){
		return this.previous(name) || (name == 'Content-type' ? this.xhr.contentType || null : null);
	},
	
	cancel: function(){
		cleanup(this.xhr);
		return this.previous();
	}

});

})();