代码
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
img {
display: inline-block;
width: 100px;
height: 150px;
}
</style>
</head>
<body>
<div id="app"></div>
<script>
window.onload = function () {
var app = document.getElementById('app');
// 追加50个灯泡
for (var i = 0; i < 50; i++) {
app.innerHTML += '<img src="images/bright.jpg" alt="">';
}
var imgs = document.getElementsByTagName('img');
for (var i = 0; i < imgs.length; i++) {
imgs[i].flag = true; // 每一个灯泡都配备一个开关 默认值都是 true-亮
imgs[i].onmouseover = function () {
if (this.flag) { // 判断 当前 img 身上的开关状态
this.src = 'images/dark.jpg';
this.flag = false; // 改变当前img 身上开关状态
} else {
this.src = 'images/bright.jpg';
this.flag = true;
}
}
}
}
</script>
</body>
</html>
效果