function showMenu(obj){
    	if(document.getElementById){

    	var el = document.getElementById(obj);
    	var ar = document.getElementById("menu").getElementsByTagName("div");

    			for (var i=0; i<ar.length; i++){
   				ar[i].style.visibility = "hidden";
		    	}

    			el.style.visibility = "visible";

    }
}


    function hideMenu(obj){
    	if(document.getElementById){

    	var el = document.getElementById(obj);
    	var ar = document.getElementById("menu").getElementsByTagName("div");

    			for (var i=0; i<ar.length; i++){
   				ar[i].style.visibility = "hidden";
		    	}


    }
}