function $(id) {return document.getElementById(id);}
function changeImg(n) {
	$("roll-img").src="images/index/roll_b0"+n+".jpg";
	var li = $("roll-s").getElementsByTagName("li");
	for(var i = 0;i < li.length;i ++){
		li[i].className = "";
		$("roll-txt" + (i+1)).style.display = "none";
	}
	li[n-1].className = "roll-on";
	$("roll-txt" + n).style.display = "block";
}

function changeBox(n) {
	var li = $("tab").getElementsByTagName("li");
	var ul = $("tab-box").getElementsByTagName("ul");
	for(var i = 0;i < li.length;i ++){
		li[i].className = "";
		ul[i].style.display = "none";
	}
	li[n-1].className = "tab-on";
	ul[n-1].style.display = "block";
}