<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <div style=" display: none; z-index: 10; position: fixed; top: 50%; left:50%; margin-top:-200px; margin-left: -250px; background-color: white;height: 400px; width: 500px; "></div> <div style=" display: none; z-index:9; position: fixed; background-color: black; top:0; left:0; bottom:0; right:0; opacity: 0.5; "></div> <div style="height: 5000px; background-color: greenyellow"> sdada </div> </body> </html>
