//栏目切换
function swap(n,len,obj){
	for(var i=1;i<=len;i++){
		var curB=document.getElementById(obj+"_t"+i);
		var curC=document.getElementById(obj+"_"+i);
		if(n==i){
			curB.className="active"
			curC.style.display="block";
		}else{
			curB.className="normal"
			curC.style.display="none";
		}
	}
}