报错myFocus.set() undefined
我的代码如下
<head>
<meta charset="UTF-8">
<title>慕课网</title>
<link rel="stylesheet" href="css/index.css">
<script scr="js/myfocus-2.0.1.min.js" type="text/javascript" charset="utf-8"></script>
<script scr="js/mf-pattern/mF_YSlider.js" type="text/javascript" charset="utf-8"></script>
<link rel="stylesheet" href="js/mf-pattern/mF_YSlider.css">
<script type="text/javascript">
myFocus.set({
id:'picBox'
});
</script>
</head>
<div class="ad" id="picBox">
<div class="pic">
<ul>
<li><img src="imagescr/ad2.jpg" alt="展示图片"></li>
<li><img src="imagescr/ad3.jpg" alt="展示图片"></li>
<li><img src="imagescr/ad4.jpg" alt="展示图片"></li>
</ul>
</div>
</div>焦点图没效果，调试发现浏览器报错说：myFocus.set() undefined，可是检查了JS文件引入路径，发现没问题，求大神指教
