// JavaScript Document


function getRSS(url)
{
	
    /*Define XMLHttpRequest Obj*/
    if (window.ActiveXObject){ //IE
        xhr = new ActiveXObject("Microsoft.XMLHTTP");
	}else if (window.XMLHttpRequest){ //other
	try {
    netscape.security.PrivilegeManager.enablePrivilege("UniversalBrowserRead");
   } catch (e) {
    alert("Permission UniversalBrowserRead denied.");
   }
        xhr = new XMLHttpRequest();
	}else{
        alert("your browser does not support AJAX");
	}
    /*set up XHR object*/
    xhr.open("GET",url,true);
	alert('kitty');
    /*Make sure we get non cached version from server*/
    xhr.setRequestHeader("Cache-Control", "no-cache");
    xhr.setRequestHeader("Pragma", "no-cache");

    /*Don't move on until server response becomes available*/
    xhr.onreadystatechange = function() {
        if (xhr.readyState == 4)
        {
            if (xhr.status == 200)
            {
                /*Make sure response is not empty*/
                if (xhr.responseText != null)
                    processRSS(xhr.responseXML);
                else
                {
                    alert("Failed to receive RSS file from the server - file not found.");
                    return false;
                }
            }
            else
                alert("Error code " + xhr.status + " received: " + xhr.statusText);
        }
    }

    /*E*/
    xhr.send(null);
}

function processRSS(rssxml)
{
    RSS = new RSS2Channel(rssxml);
    showRSS(RSS);
}

function RSS2Channel(rssxml)
{
    /*A*/
    /*required string properties*/
    this.title;
    this.link;
    this.description;

    /*array of RSS2Item objects*/
    this.items = new Array();

    /*B*/
    var chanElement = rssxml.getElementsByTagName("channel")[0];
    var itemElements = rssxml.getElementsByTagName("item");

    /*C*/
    for (var i=0; i<itemElements.length; i++)
    {
        Item = new RSS2Item(itemElements[i]);
        this.items.push(Item);
    }

}

function RSS2Item(itemxml)
{
    /*A*/
    /*required properties (strings)*/
    this.title;
    this.link;
    this.description;

    this.guid;
   

    /*C*/
    this.guid = new RSS2Guid(itemxml.getElementsByTagName("guid")[0]);
}

function RSS2Guid(guidElement)
{
    if (guidElement == null) {
        this.isPermaLink = null;
        this.value = null;
    } else {
        this.isPermaLink = guidElement.getAttribute("isPermaLink");
        this.value = guidElement.childNodes[0].nodeValue;
    }
}

function showRSS(RSS)
{
    /*Dynamically generate the html tags*/
    var imageTag = "<img id='chan_image'";
    var startItemTag = "<div id='item'>";
    var startTitle = "<div id='item_title'>";
    var startLink = "<div id='item_link'>";
    var startDescription = "<div id='item_description'>";
    var endTag = "</div>";

    /*traverse string properties of RSS2Category obj*/
    var properties = new Array("title","link","description");
    for (var i=0; i<properties.length; i++)
    {
        eval("document.getElementById('chan_"+properties[i]+"').innerHTML = ''"); /*B1*/
        curProp = eval("RSS."+properties[i]);
        if (curProp != null)
            eval("document.getElementById('chan_"+properties[i]+"').innerHTML = curProp"); /*B2*/
    }

    
    /*show the image*/
    document.getElementById("chan_image_link").innerHTML = "";
    if (RSS.image.src != null)
    {
        document.getElementById("chan_image_link").href = RSS.image.link; /*C1*/
        document.getElementById("chan_image_link").innerHTML = imageTag
            +" alt='"+RSS.image.description
            +"' width='"+RSS.image.width
            +"' height='"+RSS.image.height
            +"' src='"+RSS.image.url
            +"' "+"/>"; /*C2*/
    }


    /*Display items in rss obj*/
    document.getElementById("chan_items").innerHTML = "";
    for (var i=0; i<RSS.items.length; i++)
    {
        item_html = startItemTag;
        item_html += (RSS.items[i].title == null) ? "" : startTitle + RSS.items[i].title + endTag;
        item_html += (RSS.items[i].link == null) ? "" : startLink + RSS.items[i].link + endTag;
        item_html += (RSS.items[i].description == null) ? "" : startDescription + RSS.items[i].description + endTag;
        item_html += endTag;
        document.getElementById("chan_items").innerHTML += item_html; /*D1*/
    }

    return true;
}