                        課程
                    
                        /前端開發(fā)
                        
                            /JavaScript
                        
                        /焦點圖輪播特效

焦點圖問題,為什么到第一張到第二張好使,往后就不好使了呢...求大神解答

<!DOCTYPE?html>

<html>
<head>
<meta charset="UTF-8">
<title>焦點輪播圖</title>
<style type="text/css">
* {
??? margin: 0;
??? padding: 0;
??? text-decoration: none;
}
body {
??? padding: 20px;
}
#container {
??? width: 600px;
??? height: 400px;
??? overflow: hidden;
??? position: relative;
}
#list {
??? width: 3000px;
??? height: 400px;
??? position: absolute;
??? z-index: 1;
}
#list img {
??? float: left;
}
#buttons {
??? position: absolute;
??? height: 10px;
??? width: 100px;
??? z-index: 2;
??? bottom: 20px;
??? left: 250px;
}
#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: #ff4509;
}
.arrow {
??? cursor: pointer;
??? display: none;
??? line-height: 39px;
??? text-align: center;
??? font-size: 36px;
??? font-weight: bold;
??? width: 40px;
??? height: 40px;
??? position: absolute;
??? z-index: 2;
??? top: 180px;
??? background-color: rgba(0, 0, 0, .3);
??? color: #fff;
}
.arrow:hover {
??? background-color: rgba(0, 0, 0, .7);
}
#container:hover .arrow {
??? display: block;
}
#prev {
??? left: 20px;
}
#next {
??? right: 20px;
}
</style>
<script type="text/javascript">
??????? function slidePic() {
??????????? left = list.offsetLeft;
??????????? var timer = setInterval(function() {
??????????????? if (left-list.offsetLeft == 600) {
??????????????????? clearInterval(timer);
??????????????? }
??????????????? else {
??????????????????? list.style.left = list.offsetLeft + (-10) + "px";
??????????????? }
??????????? }, 30);
??????? }????????????????? ?
??????? window.onload = function() {
??????????????? var container = document.getElementById('container');
??????????????? var list = document.getElementById('list');
??????????????? var buttons = document.getElementById('buttons').getElementsByTagName('span');
??????????????? var prev = document.getElementById('prev');
??????????????? var next = document.getElementById('next');
??????????????? var index = 1;
??????????????? var len = 5;
??????????????? var animated = false;? ?
??????????????? var interval = 3000;
??????????????? var j = 1;
??????????????? for (j = 1; j <= len; j++) {
?????????????????????? var timer1 = setTimeout(function() {
??????????????????????????? slidePic();
??????????????????????? },3000);
??????????????????? }??????????????????? ?
??????? }

??? </script>
</head>
<body>

<div id="container">
??? <div id="list">
??????? <img src="img/1.jpg" alt="1"/>
??????? <img src="img/2.jpg" alt="2"/>
??????? <img src="img/3.jpg" alt="3"/>
??????? <img src="img/4.jpg" alt="4"/>
??????? <img src="img/5.jpg" alt="5"/>
??? </div>
??? <div id="buttons">
??????? <span index="1" class="on"></span>
??????? <span index="2"></span>
??????? <span index="3"></span>
??????? <span index="4"></span>
??????? <span index="5"></span>
??? </div>
??? <a href="javascript:;" id="prev" class="arrow"><</a>
??? <a href="javascript:;" id="next" class="arrow">></a>
</div>

</body>
</html>