cookie 常用于识别用户。cookie 是服务器留在用户计算机中的小文件。每当相同的计算机通过浏览器请求页面时，它同时会发送 cookie。通过 PHP，您能够创建并取回 cookie 的值。-Stay in the user s computer file. Every time the same computer via a browser request page, it will send a cookie at the same time. By PHP, you can create and retrieve cookie values.