The best things in using PHP are that it is extremely simple for a newcomer, but offers many advanced features for a professional programmer.
PHP가 다른 Clien-side Javascrip와 구별되는 것은 이 코드가 서버에서 실행된다는 것이다. If you were to have a script similar to the above on your server, the client would receive the results of running that script, with no way of determining what the underlying code may be. You can even configure your web server to process all your HTML files with PHP, and then there's really no way that users can tell what you have up your sleeve.