js简版图片左右切换功能

function leftMove(obj,direction,lis){
    var num = 0;
    var liWidth = lis[0].offsetWidth;
    setInterval(function(){
      if(num<parseInt(liWidth/10)){
        if(direction=="left" && obj.offsetLeft<0){
          obj.style.left = obj.offsetLeft + 10 + "px";
          num == parseInt(liWidth/10)-1 ? (obj.style.left = obj.offsetLeft + liWidth%10 + "px"):null;
        }
        else if(direction=="right" && obj.offsetLeft>-liWidth*(lis.length-1)){
          obj.style.left = obj.offsetLeft - 10 + "px";
          num == parseInt(liWidth/10)-1 ? (obj.style.left = obj.offsetLeft - liWidth%10 + "px"):null;
        }
      }
      num++;
    },10)
  }