var ContentListHandler = Class.create();
var activeItem;

ContentListHandler.prototype =
{
    initialize: function(contentHolderID, url, defaultItem)
    {
        this.url = url;
        this.contentHolderID = contentHolderID;

        Event.observe(window, "load", (function()
        {
            this.contentHolder = $(this.contentHolderID);
            if (!activeItem)
            {
                defaultItem = $(defaultItem);
                activeItem = defaultItem;
                this.displayContent(defaultItem, defaultItem.rel);
            }
        }).bind(this));
    },

    displayContent: function(sender, id)
    {
        var url = this.url;
        url = url.replace("{0}", id);
        updateContainer(this.contentHolder, url);

        Object.extend(sender);
        if (activeItem)
        {
            activeItem.removeClassName("active");
        }

        sender.addClassName("active");
        activeItem = sender;
    }
}