function chageIndex(indexNum,num,menuName,contentName,myClassName){
	var i="";
	for (i=1;i<=num;i++){
		document.getElementById(menuName+i).className=myClassName+"2";
		document.getElementById(contentName+i).style.display="none";
	}
	document.getElementById(menuName+indexNum).className=myClassName+"1";
	document.getElementById(contentName+indexNum).style.display="block";
}