function rssParser(xml) {
	var v = Try.these(
    	function() {
            return xml.getElementsByTagName("rss")[0].getAttribute("version") ? "2.0" : false;
        },
        function() {
            return xml.getElementsByTagName("rdf:RDF")[0].getAttribute("xmlns") ? "1.0" : false;
        },	
        function() {
            return xml.getElementsByTagName("feed")[0].getAttribute("xmlns") ? "atom" : false;
        }
     )

     switch(v) {
        case "2.0"  : return new rssParser2(xml); break;
        case "1.0"  : return new rssParser1(xml); break;
        case "atom" : return new rssParserAtom(xml); break;
        default     : return false;
     }
};


// Rss 2.0 Calss
var rssParser2 = Class.create();
Object.extend(rssParser2.prototype, {
    initialize    : function(xml) {
        var channel = xml.getElementsByTagName("channel")[0];
        this.title  = channel.getElementsByTagName("title")[0].firstChild.nodeValue;
        this.link   = channel.getElementsByTagName("link")[0].firstChild.nodeValue;
        if(channel.getElementsByTagName("image")[0]) {
            var images   = channel.getElementsByTagName("image")[0];
            this.image   = {
                "url"    : images.getElementsByTagName("url")[0].firstChild.nodeValue,
                "title"  : images.getElementsByTagName("title")[0].firstChild.nodeValue,
                "link"   : images.getElementsByTagName("link")[0].firstChild.nodeValue
            };
        }
        else {
            this.image = {
                "url"    : "",
                "title"  : "",
                "link"   : ""
            }
        }

        this.description = Try.these (
            function() {
                return channel.getElementsByTagName("description")[0].firstChild.nodeValue;
            },
            function() { return "" }
        );

        this.language    = Try.these (
            function() {
                return channel.getElementsByTagName("language")[0].firstChild.nodeValue;
            },
            function() {
                return channel.getElementsByTagName("dc:language")[0].firstChild.nodeValue;
            },
            function() { return ""}
        );

        this.pubDate     = Try.these(
            function() {
                return channel.getElementsByTagName("pubDate")[0].firstChild.nodeValue;
            },
            function() {
                return channel.getElementsByTagName("lastBuildDate")[0].firstChild.nodeValue;
            },
            function() { return ""; }
        );

        var items = new Array();
        $A(channel.getElementsByTagName("item")).each(function(i){
            items.push({
                "category" : Try.these(
                    function() {
                        return i.getElementsByTagName("category")[0].firstChild.nodeValue;
                    },
                    function() { return "" }
                ),
                "title" : i.getElementsByTagName("title")[0].firstChild.nodeValue,
                "link"    : i.getElementsByTagName("link")[0].firstChild.nodeValue,
                "forecastLen"    : i.getElementsByTagName("yweather:forecast").length,
                "forecast1"    : i.getElementsByTagName("yweather:forecast")[0],
                "forecast2"    : i.getElementsByTagName("yweather:forecast")[1],
                "forecast3"    : i.getElementsByTagName("yweather:forecast")[2],
                "forecast4"    : i.getElementsByTagName("yweather:forecast")[3],
                "forecast5"    : i.getElementsByTagName("yweather:forecast")[4],
                "description" : Try.these (
                    function() {
                        return i.getElementsByTagName("description")[0].firstChild.nodeValue;
                    },
                    function() { return "" }
                ),
                "pubDate" : Try.these (
                    function() {
                        return i.getElementsByTagName("pubDate")[0].firstChild.nodeValue;
                    },
                    function() {
                        return i.getElementsByTagName("dc:date")[0].firstChild.nodeValue;
                    },
                    function() { return "" }
                )
            })
        })
        this.item = items;
    }
});

// Rss 1.0 Calss
var rssParser1 = Class.create();
Object.extend(rssParser1.prototype, {
    initialize    : function(xml) {
        var channel = xml.getElementsByTagName("channel")[0];
        var images  = xml.getElementsByTagName("image")[0];
        this.title  = channel.getElementsByTagName("title")[0].firstChild.nodeValue;
        this.link   = channel.getElementsByTagName("link")[0].firstChild.nodeValue;
        this.image  = {
            "url"   : images.getElementsByTagName("url")[0].firstChild.nodeValue,
            "title" : images.getElementsByTagName("title")[0].firstChild.nodeValue,
            "link"  : images.getElementsByTagName("link")[0].firstChild.nodeValue
        };
        this.description = channel.getElementsByTagName("description")[0].firstChild.nodeValue;
        this.language    = channel.getElementsByTagName("dc:language")[0].firstChild.nodeValue;
        this.pubDate     = channel.getElementsByTagName("dc:date")[0].firstChild.nodeValue;
        var items        = xml.getElementsByTagName("item");
        var itemValue    = new Array();
        for(var i = 0; i < items.length; i++) {
            itemValue.push({
                "category"   : items[i].getElementsByTagName("category")[0].firstChild.nodeValue,
                "title"      : items[i].getElementsByTagName("title")[0].firstChild.nodeValue,
                "link"       : items[i].getElementsByTagName("link")[0].firstChild.nodeValue,
                "description":
				    items[i].getElementsByTagName("description")[0].firstChild.nodeValue,
                "pubDate"    : items[i].getElementsByTagName("dc:date")[0].firstChild.nodeValue
            });
        };
        this.item = itemValue;
    }
});

var rssParserAtom = Class.create();
Object.extend(rssParserAtom.prototype, {
    initialize    : function(xml) {
        this.title   = xml.getElementsByTagName("title")[0].firstChild.nodeValue;
        this.link    = xml.getElementsByTagName("link")[0].getAttribute("href");
        this.image   = {
            "url"    : "",
            "title"  : "",
            "link"   : ""
        };

        this.description = xml.getElementsByTagName("info")[0].firstChild.nodeValue;
        this.language    = "";
        this.pubDate     = xml.getElementsByTagName("modified")[0].firstChild.nodeValue;
        var items        = xml.getElementsByTagName("entry");
        var itemValue    = new Array();
        for(var i = 0; i < items.length; i++) {
            itemValue.push({
                "category"   : "",
                "title"      : items[i].getElementsByTagName("title")[0].firstChild.nodeValue,
                "link"       : items[i].getElementsByTagName("link")[0].getAttribute("href"),
                "description":items[i].getElementsByTagName("summary")[0].firstChild.nodeValue,
                "pubDate"    : items[i].getElementsByTagName("created")[0].firstChild.nodeValue
            });
        };
        this.item = itemValue;
    }
});