function changeTab() {
	with (document.getElementById("afterrace")) className = (className == "contents tab1") ? "contents tab2" : "contents tab1";
}

// anchor click movement
function changeTabAfter() {
	var tabObj = document.getElementById("afterrace");
	if(tabObj.className == "contents tab2") {
		with (document.getElementById("afterrace")) className = "contents tab1";
	}
}

function changeTabBefore() {
	var tabObj = document.getElementById("afterrace");
	if(tabObj.className == "contents tab1") {
		with (document.getElementById("afterrace")) className = "contents tab2";
	}
}