function createAjaxObj(){
    var httprequest=false;
    if (window.XMLHttpRequest){ // if Mozilla, Safari etc
        httprequest=new XMLHttpRequest();
        if (httprequest.overrideMimeType)
            httprequest.overrideMimeType('text/xml');
    }
    else if (window.ActiveXObject){ // if IE
        try {
            httprequest=new ActiveXObject("Msxml2.XMLHTTP");
        }
        catch (e){
            try{
                httprequest=new ActiveXObject("Microsoft.XMLHTTP");
            }
            catch (e){}
        }
    }
    return httprequest;
}

// -------------------------------------------------------------------
// Main RSS Ticker Object function
// rss_ticker(RSS_id, cachetime, divId, divClass, delay, optionalswitch)
// -------------------------------------------------------------------

function rss_ticker(divId, divClass, delay, optionalswitch){
	
    this.tickerid=divId; //ID of ticker div to display information
    this.delay=delay; //Delay between msg change, in miliseconds.
    this.logicswitch=(typeof optionalswitch!="undefined")? optionalswitch : -1;
    this.mouseoverBol=0; //Boolean to indicate whether mouse is currently over ticker (and pause it if it is)
    this.pointer=0;
    this.ajaxobj=createAjaxObj();
    document.write('<div id="'+divId+'" class="'+divClass+'">Initializing ticker...</div>');
    this.getAjaxcontent();
}

// -------------------------------------------------------------------
// getAjaxcontent()- Makes asynchronous GET request to "rss/news.xml" with the supplied parameters
// -------------------------------------------------------------------

rss_ticker.prototype.getAjaxcontent=function(){
    if (this.ajaxobj){
        var instanceOfTicker=this;
        //var parameters="id="+encodeURIComponent(this.RSS_id)+"&cachetime="+this.cachetime+"&bustcache="+new Date().getTime()
        this.ajaxobj.onreadystatechange=function(){
            instanceOfTicker.initialize()
            }
        this.ajaxobj.open('GET', "./rss/news.xml", true);
        this.ajaxobj.send(null);
    }
}

// -------------------------------------------------------------------
// initialize()- Initialize ticker method.
// -Gets contents of RSS content and parse it using JavaScript DOM methods 
// -------------------------------------------------------------------

rss_ticker.prototype.initialize=function(){ 
    if (this.ajaxobj.readyState == 4){ //if request of file completed
        if (this.ajaxobj.status==200){ //if request was successful
            var xmldata=this.ajaxobj.responseXML;
            if (xmldata.getElementsByTagName("item").length==0){ //if no <item> elements found in returned content
                document.getElementById(this.tickerid).innerHTML="<b>Error</b> fetching remote RSS feed!<br />"+this.ajaxobj.responseText;
                return;
            }
            var instanceOfTicker=this;
            this.feeditems=xmldata.getElementsByTagName("item");

            //Cycle through RSS XML object and store each piece of the item element as an attribute of the element
            for (var i=0; i<this.feeditems.length; i++){
                this.feeditems[i].setAttribute("ctitle", this.feeditems[i].getElementsByTagName("title")[0].firstChild.nodeValue);
                this.feeditems[i].setAttribute("clink", this.feeditems[i].getElementsByTagName("link")[0].firstChild.nodeValue);
                this.feeditems[i].setAttribute("cdescription", this.feeditems[i].getElementsByTagName("description")[0].firstChild.nodeValue);
            }
            document.getElementById(this.tickerid).onmouseover=function(){
                instanceOfTicker.mouseoverBol=1
                }
            document.getElementById(this.tickerid).onmouseout=function(){
                instanceOfTicker.mouseoverBol=0
                }
            this.rotatemsg();
        }
    }
}

// -------------------------------------------------------------------
// rotatemsg()- Rotate through RSS messages and displays them
// -------------------------------------------------------------------

rss_ticker.prototype.rotatemsg=function(){
    var instanceOfTicker=this;
    if (this.mouseoverBol==1) //if mouse is currently over ticker, do nothing (pause it)
        setTimeout(function(){
            instanceOfTicker.rotatemsg()
            }, 100);
    else{
        var tickerDiv=document.getElementById(this.tickerid);
        var tickercontent='<a href="'+this.feeditems[this.pointer].getAttribute("clink")+'">'+this.feeditems[this.pointer].getAttribute("ctitle")+'</a>';
        if (this.logicswitch=="showdescription")
            tickercontent+='<br><i>'+this.feeditems[this.pointer].getAttribute("cdescription")+'</i>';
        tickerDiv.innerHTML=tickercontent
        this.pointer=(this.pointer<this.feeditems.length-1)? this.pointer+1 : 0;
        setTimeout(function(){
            instanceOfTicker.rotatemsg()
            }, this.delay); //update container every second
    }
}