为什么我尝试打开 https://localhost:8000 时出现错误

Why I am getting error when I was trying to open https://localhost:8000

当我需要为我的 PHP 代码打开本地主机站点 https://localhost:8000 时。 所以我在我的 VS 代码终端中写了这一行

php-Slocalhost:8000

但我收到错误消息。

已复制粘贴

php : The term 'php' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was 
included, verify that the path is correct and try again.
At line:1 char:1
+ php -S localhost:8000
+ ~~~
    + CategoryInfo          : ObjectNotFound: (php:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

请看php : The term 'php' is not recognized as the name of a cmdlet, function, script file, or operable program