jquery+css实现简单的图片轮播效果

<div class="banner">
    <!--第一张图片为最后一张，用来做轮播连接使用，所以一开始显示的第一章，应是第二张图片，这里图片的宽度为1170px，所以一开始left为-1170px，同理最后一张图也为第一张图。-->
  <div class="pic-list" style="left: -1170px">
    <img src="/static/img/4.jpg" alt="">
    <img src="/static/img/1.jpg" alt="">
    <img src="/static/img/2.jpg" alt="">
    <img src="/static/img/3.jpg" alt="">
    <img src="/static/img/4.jpg" alt="">
    <img src="/static/img/1.jpg" alt="">
  </div>
  <div id="buttons">
    <!-- 确保span的数量跟img数量一样多，不包括第一张img和最后一张img-->
    <span class='on'></span>
    <span></span>
    <span></span>
    <span></span>
  </div>
  <a href="javascript:;" class="arrow" id="prev">&lt;</a>
  <a href="javascript:;" class="arrow" id="next">&gt;</a>
</div>

.banner{
  width: 100%;
  height: 500px;
  overflow: hidden;
  position: relative;

}
.banner a{
  text-decoration: none;
}
.banner .pic-list{
  width: 10000px;
  height: 500px;
  position: absolute;
  z-index: 1;
}
.banner .pic-list img{
  width: 1170px;
  float: left;
}
#buttons{
  position: absolute;
  z-index: 2;
  height: 10px;
  bottom: 20px;
  left: 550px;

}
#buttons span{
  cursor: pointer;
  float: left;
  border: 1px solid #fff;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #333;
  margin-right: 5px;
}
#buttons .on{
  background: orange;
}
.arrow{
  cursor: pointer;
  line-height: 36px;
  text-align: center;
  font-size: 20px;
  font-weight: bold;
  width: 40px;
  height: 40px;
  position: absolute;
  z-index: 2;
  top: 200px;
  background: rgba(0,0,0,0.5);
  color: #fff;
  display: none;
}
.banner:hover .arrow{display: block;}

#prev{
  left: 20px;
}
#next{
  right:20px;
}

$(document).ready(function(){
  var picNum = 4;//图片数量，根据实际修改
  var picWidth = 1170;//图片的宽度，根据实际修改
  var picMaxWidth = -1 * picNum * picWidth;
  var currentPic = 1;
  var next = $('#next');
  var prev = $('#prev');
  var flag = false;

  prev.on('click',function(){
    if(!flag){
      calPx(1170);
      currentPic--;
      if (currentPic < 1) {
        currentPic = picNum;
      }
      $('#buttons span').eq(currentPic-1).addClass('on').siblings().removeClass('on');
    }
  });

  next.on('click',function(){
    if(!flag){
      calPx(-1170);
      currentPic++;
      if (currentPic > picNum) {
        currentPic = 1;
      }
      $('#buttons span').eq(currentPic-1).addClass('on').siblings().removeClass('on');
    }


  });
  $('.banner').on('mouseover',function(){
    stop();
  }).on('mouseout',function(){
    play();
  })
  function nextClick(){
    next.click();
  }
  function play(){
    setInt = setInterval(nextClick,2000);
  }
  function stop(){
    clearInterval(setInt);
  }

  function calPx(leftPx){
    flag = true;
    var left = parseInt($('.pic-list').css('left'));
    var newLeft = left+leftPx;
    var time = 300;
    var interval = 10;
    var speed = leftPx/(time/interval);

    function go(){
      var left = parseInt($('.pic-list').css('left'));
      if((speed < 0 && left > newLeft) || (speed > 0 && left < newLeft)){
        $('.pic-list').css('left', (left + speed) + 'px');
        setTimeout(go,interval);
      }else{
        flag = false;
        if( newLeft > -1170){
          newLeft = picMaxWidth;
        }else if (newLeft < picMaxWidth ) {
          newLeft = -1170;
        }
        $('.pic-list').css('left',newLeft + 'px');
      }
    }
    go();

  }
  play();

});