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<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style>
* {
margin: 0;
padding: 0;
}
#container {
margin: 10px 20px;
}
#container li {
float: left;
list-style: none;
width: 60px;
height: 60px;
}
</style>
</head>
<body>
<div id="container">
<img src="img/picture-1.jpg" alt="狗屎">
<ul id="items">
<li><img src="img/thumb-1.jpg" alt=""></li>
<li><img src="img/thumb-2.jpg" alt=""></li>
<li><img src="img/thumb-3.jpg" alt=""></li>
</ul>
</div>
<script>
var img = document.querySelector('#container>img');
var images = document.querySelectorAll('#items img');
for (var i = 0; i < images.length; i += 1) {
// 事件回调函数在for循环的时候并没有执行所以也取不到循环变量i当前的值
// JavaScript是动态弱类型语言可以在运行时动态的添加(或删除)对象的属性
images[i].picture = 'img/picture-' + (i + 1) + '.jpg';
images[i].addEventListener('mouseover', function(evt) {
img.src = evt.target.picture;
});
}
</script>
</body>
</html>