var speed=10//速度数值越大速度越慢
  var letian=document.getElementById("letian");
  var letian1=document.getElementById("letian1");
  var letian2=document.getElementById("letian2");
  letian2.innerHTML=letian1.innerHTML;
  function Marquee(){
  if(letian2.offsetWidth-letian.scrollLeft<=0)
  letian.scrollLeft-=letian1.offsetWidth
  else{
  letian.scrollLeft++
  }
  }
  var MyMar=setInterval(Marquee,speed)
  letian.onmouseover=function() {clearInterval(MyMar)}
  letian.onmouseout=function() {MyMar=setInterval(Marquee,speed)}