For example, if class="nav-link active" is not set in the a tag in the capsule navigation tab page, it will not be displayed correctly. You also need to quote <script src="https://cdn.staticfile.org/popper.js/1.15.0/umd/popper.min.js"></script>, which requires a lot of code. displayed correctly?
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
I see