//<![CDATA[
var curFrame=1;//当前标签
var frameheight = 175;//单层高度
var speed = 5;//滚动速度
var waitTime = 4000;//自动播放间隔时间
var scrollItv;
var autoItv;
var maindiv = document.getElementById("main");
autoItv = setInterval(autoSlide, waitTime);
function slideTo(id){
 curFrame = id;
 var curTop = maindiv.scrollTop;
 var tarTop = frameheight*(id-1);
 var step = curTop>tarTop?-speed:speed;
 clearInterval(autoItv);
 clearInterval(scrollItv);
 scrollItv = setInterval(function(){
  maindiv.scrollTop += step;
  if(Math.abs(maindiv.scrollTop-tarTop)<speed){
   clearInterval(scrollItv);
   maindiv.scrollTop = tarTop;
   autoItv = setInterval(autoSlide, waitTime);
  }
 },20);
 for(i=1;i<=4;i++){
  document.getElementById('led'+i).className='NUM1';
 }
 document.getElementById('led'+curFrame).className='NUM2';
}
function autoSlide(){
 if(curFrame<4){curFrame++;}else{curFrame=1;}
 slideTo(curFrame);
}
//]]>