Generally speaking, there are two reasons:
1. The first is that the binding is not cancelled, such as $("#test").unbind("click");$("#test").click (function(){....});
2. This is because the same js file is referenced multiple times on different pages, which may also cause repeated submission of requests.
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
