JQuery循环滚动图片代码

function refresh() {
    var s = $(".box1");
    if (!s.is(":animated"))
        $(".box1").animate({ marginLeft: "0px" }, "slow", function () {
            $('.box1 img:first').before($('.box1 img:last'));
   $(".box1").css("margin-left", "-206px");
        });
    }

 

<div class="frame"><div class="box1"><img src="img/001.png" alt="" /><img src="img/002.png" alt="" /><img src="img/003.png" alt="" /><img src="img/004.png" alt="" /></div></div>
        <button type="button"><<</button><button type="button" onclick="refresh()">>></button>

 

 

.box1
      {
          width:1200px;
          overflow:hidden;
          margin-left:-206px;
      }

.frame
     {
         width:620px;
         overflow:hidden;
     }

图片宽度默认206px，没设定