Collection
Collection
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<img src="./images/3.jpg" alt="" width="500" id="img">
</body>
<script>
var img = document.getElementById('img');
img.onload = function(){
//alert('图片加载成功');
}
img.onerror = function(){
//alert('图片加载失败')
img.src="./images/2.jpg";
}
</script>
</html>点击 "运行实例" 按钮查看在线实例
