function Topmenu(){

    this.length = 0;

    this.init = function(len){
        this.length = len;    
    };

    this.setStyle = function(currentIndex){
        var i = 0;
        while(i < this.length){
            var topmenuItem = document.getElementById("topmenu_" + i);
            if(topmenuItem != null){
                if(currentIndex == i){
                    topmenuItem.className = "topmenu-item-s";
                }
                else{
                    topmenuItem.className = "topmenu-item";
                }
            }
            i++;
        }
    };
}

var topmenu = new Topmenu();