var SlideList = new Class({ 
    initialize: function(menu, defalutValue, options) { 
        this.setOptions(this.getOptions(), options); 
        this.menu = $(menu), 
        this.menu.getElements('li').each(function(item){ 
                       if(defalutValue == item.getElement('a').getText()){
                           if(!item.hasClass('current')){
                             item.addClass('current');
                           }
                       } else {
                             item.removeClass('current');
                       }
        });                
        this.current = this.menu.getElement('li.current'); 

        this.menu.getElements('li').each(function(item){ 
                       item.addEvent('mouseover', function(){ this.moveBg(item); }.bind(this)); 
                       item.addEvent('mouseout', function(){ this.moveBg(this.current); }.bind(this)); 
                       //item.addEvent('click', function(event){ this.clickItem(event, item); }.bind(this)); 
        }.bind(this)); 
        

          
        this.back = new Element('li').addClass('back').adopt(new Element('div').addClass('left')).injectInside(this.menu);            
        this.back.fx = this.back.effects(this.options); 
        if(this.current) this.setCurrent(this.current); 
        
 
    }, 
    setCurrent: function(el, effect){ 
        this.back.setStyles({left: (el.offsetLeft)+'px', width: (el.offsetWidth)+'px'}); 
        (effect) ? this.back.effect('opacity').set(0).start(1) : this.back.setOpacity(1); 
        this.current = el; 
    }, 

    getOptions: function(){ 
        return { 
        transition: Fx.Transitions.sineInOut, 
        duration: 500, 
        wait: false, 
        onClick: Class.empty 
       }; 
    },  
    clickItem: function(event, item) { 
        if(!this.current) 
            this.setCurrent(item, true); 
        this.current = item; 
        this.options.onClick(new Event(event), item); 
    },   
    moveBg: function(to) { 
        if(!this.current) return; 
        this.back.fx.custom({ 
        left: [this.back.offsetLeft, to.offsetLeft], 
        width: [this.back.offsetWidth, to.offsetWidth] 
        }); 
    }          

});

SlideList.implement(new Options);