声明了浏览器用于 HTTP 请求的用户代理头的值

    1. <!DOCTYPE html>
    2. <html lang="en">
    3. <head>
    4.     <meta charset="UTF-8">
    5.     <meta name="viewport" content="width=device-width, initial-scale=1.0">
    6.     <title>Document</title>
    7. </head>
    8. <body>
    9.     <script>
    10.         console.log(navigator.userAgent)
    11.     </script>
    12. </body>
    13. </html>

    1.PNG