var rollCoun;
var rollPeriod = 2000;
var isStart = true;
var nn = 1;
var tt = false;
//var pageSizes = 5; //分每页5张 
var currentPage =1 ; //取得当前页码
function change_img() {
  if (isStart) {
    if (nn > rollCount) {
	  nn = 1;
	}
    setFocus(nn);
  }else{
    tt = setTimeout('change_img()', 1000);
  } 
}
function setFocus(i){
  if (tt) {
	clearTimeout(tt);
  }
  selectLayer1(i);
  nn=parseInt(i)+1;
  tt=setTimeout('change_img()', rollPeriod);
}
function selectLayer1(i){
  for (var j = 1; j <= rollCount; j++) {
	if (j == i)	{
	  document.getElementById("focus" + j).className = "";
	  document.getElementById("change" + j).className="current";
	} else {
	  document.getElementById("focus" + j).className = "hidden";
	  document.getElementById("change" + j).className="";
	}
  }
}

function overPage(action,cup){
	if (action=="1"){//减操作
		//alert("将显示"+cup);
		if (cup<=0){
			cup=1;
		}
		if(currentPage>3){
			cup=2;
		}
		if (cup==1){
			//alert("减--显示第一页");
			document.getElementById("first").style.display   =   "block";  
			document.getElementById("second").style.display   =   "none"; 
			document.getElementById("third").style.display   =   "none"; 	
		}else if (cup==2){
			//alert("减--显示第二页");
			document.getElementById("first").style.display   =   "none";  
			document.getElementById("second").style.display   =   "block"; 
			document.getElementById("third").style.display   =   "none"; 	
		}else if (cup==3){
			//alert("减--显示第三页");
			document.getElementById("first").style.display   =   "none";  
			document.getElementById("second").style.display   =   "none"; 	
			document.getElementById("third").style.display   =   "block"; 
		}
	}else if(action=="2"){//加操作
		//alert("将显示"+cup);
		if (cup<=0){
			cup=1;
		}
		if(currentPage>3){
			cup=3;
		}
		if (cup==1){
			//alert("加--显示第一页");
			document.getElementById("first").style.display   =   "block";  
			document.getElementById("second").style.display   =   "none"; 
			document.getElementById("third").style.display   =   "none"; 	
		}else if (cup==2){
			//alert("加--显示第二页");
			document.getElementById("first").style.display   =   "none";  
			document.getElementById("second").style.display   =   "block"; 
			document.getElementById("third").style.display   =   "none"; 	
		}else if (cup==3){
			//alert("加--显示第三页");
			document.getElementById("first").style.display   =   "none";  
			document.getElementById("second").style.display   =   "none"; 	
			document.getElementById("third").style.display   =   "block"; 
		}
	}
	
	currentPage=cup;
}