var curId = 1;
window.setInterval("auto_play()",4000);
function auto_play(){
	nextId = (curId + 1) % 3;
	if(nextId==0){nextId=3;}
	focus_play(nextId);
}
function focus_play(sid){
	curId = sid;
	for(var i=1;i<4;i++){
		if(i==sid){
			$("#pic_"+i).addClass("curpic");
			$("#min_"+i).addClass("curmin");
		}
		else{
			$("#pic_"+i).removeClass("curpic");
			$("#min_"+i).removeClass("curmin");
		}
	}
}