#DD{ position: relative; top: 0px; left: 0px; width: 500px; height: 300px; overflow: hidden;}#A1{ position: relative; width: 100%; height: 100%; padding-bottom: 50px; background-color: #F00;}#A2{ position: relative; width: 100%; height: 100%; border-bottom: solid 50px #000000; background-color: #F00;}#B{ position: relative; top: 0px; left: 0px; width: 100%; height: 100%; overflow-x:hidden; overflow-y:auto; background-color: #00F;}<html><head><link rel="stylesheet" href="css.css" type="text/css"></head><body><div id="DD"> <span id="A1"> <span id="B"> <ul> <li>1</li> <li>1</li> <li>1</li> <li>1</li> <li>1</li> <li>1</li> <li>1</li> <li>1</li> <li>1</li> <li>1</li> <li>1</li> <li>1</li> <li>1</li> <li>1</li> <li>1</li> <li>1</li> <li>1</li> <li>1</li> <li>1</li> <li>1</li> </ul> </span> </span></div></body></html>
It was wrong when the page was first opened, but it was right after switching the page
>
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
