function swapBtn(btn) {

	var path = document.location.pathname;
	var dir = path.split("/");
	
	var str = btn.src.substr(btn.src.length-8, 4);
	
	if(str == "over") {
		var name = btn.src.split("/");
		var name = name[name.length-1];
		var name = name.substr(0, name.length-9);
		btn.src = "menu/" + name + ".png";
	}
	else {
		var name = btn.src.split("/");
		var name = name[name.length-1];
		var name = name.substr(0, name.length-4);
		btn.src = "menu/" + name + "-over.png";
	}
}