<!doctype html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>这是一个测试</title> <link href="css/popup.css" rel="stylesheet" type="text/css" /> <script type="text/javascript" src="lib/jquery-3.3.1.min.js"></script> <script type="text/javascript" src="js/popup.js"></script> </head> <body> <div style="width: 520px;height: 470px;text-align: center;margin: auto;"> <h2 style="color: #2159f3;">测试是否成功打开</h2> </div> </body> </html>