function bianhuan(num,more){
	for (var i=1;i<=more;i++) {
	document.getElementById("zx"+i).className="";
	document.getElementById("picnav"+i).style.display="none";
	}
	for (var k=1;k<=more;k++) {
	if(num==k){
	document.getElementById("zx"+k).className="nowpic";
	document.getElementById("picnav"+k).style.display="block";
	}}
	
}