자바스크립트에서 캐러셀을 구현하는 방법

<div class="wrap" id="wrap">
 <div class="slide" id="slide">
 <ul>
  <li><a href="#" ><img src="images/slidepic1.jpg" alt=""/></a></li>
  <li><a href="#" ><img src="images/slidepic2.jpg" alt=""/></a></li>
  <li><a href="#" ><img src="images/slidepic3.jpg" alt=""/></a></li>
  <li><a href="#" ><img src="images/slidepic4.jpg" alt=""/></a></li>
  <li><a href="#" ><img src="images/slidepic5.jpg" alt=""/></a></li>
 </ul>
 <div class="arrow" id="arrow">
  <a href="javascript:;" class="prev" id="arrLeft"></a>
  <a href="javascript:;" class="next" id="arrRight"></a>
 </div>
 </div>
</div>

blockquote, body, button, dd, dl, dt, fieldset, form, h1, h2, h3, h4, h5, h6, hr, input, legend, li, ol, p, pre, td, textarea, th, ul {
 margin: 0;
 padding: 0
}
 
body, button, input, select, textarea {
 font: 12px/1.5 "Microsoft YaHei", "微软雅黑", SimSun, "宋体", sans-serif;
 color: #666;
}
 
ol, ul {
 list-style: none;
}
 
a {
 text-decoration: none;
}
 
fieldset, img {
 border: 0;
 vertical-align: top;
}
 
a, input, button, select, textarea {
 outline: none;
}
 
a, button {
 cursor: pointer;
}
 
.wrap {
 width: 1200px;
 margin: 100px auto;
}
 
.slide {
 height: 500px;
 position: relative;
}
 
.slide li {
 position: absolute;
 left: 200px;
 top: 0;
}
 
.slide li img {
 width: 100%;
}
 
.arrow {
 opacity: 0;
 position: absolute;
 top: 50%;
 z-index: 1000;
 width: 100%;
}
 
.prev, .next {
 width: 76px;
 height: 112px;
 position: absolute;
 z-index: 99;
}
 
.prev {
 left: 0;
 background: url(../images/prev.png) no-repeat;
}
 
.next {
 right: 0;
 background-image: url(../images/next.png);
}

function animate(obj, json, fn) {
 clearInterval(obj.timer);
 obj.timer = setInterval(function () {
  var flag = true;
  for (var k in json) {
  if (k === "opacity") {
   var leader = getStyle(obj, k) * 100;
   var target = json[k] * 100;
   var step = (target - leader) / 10;
   step = step > 0 ? Math.ceil(step) : Math.floor(step);
   leader = leader + step;
   obj.style[k] = leader / 100;
  } else if (k === "zIndex") {
   obj.style.zIndex = json[k];
  } else {
   var leader = parseInt(getStyle(obj, k)) || 0;
   var target = json[k];
   var step = (target - leader) / 10;
   step = step > 0 ? Math.ceil(step) : Math.floor(step);
   leader = leader + step;
   obj.style[k] = leader + "px";
  }
  if (leader != target) {
   flag = false;
  }
  }
  if (flag) {
  clearInterval(obj.timer);
  if (fn) {
   fn();
  }
  }
 }, 15);
 }
 function getStyle(obj, attr) {
 if (window.getComputedStyle) {
  return window.getComputedStyle(obj, null)[attr];
 } else {
  return obj.currentStyle[attr];
 }
 }