What is PHP?

PHP is a server-side scripting language: when a visitor requests a page, the web server hands the PHP file to the PHP runtime, which runs the code and sends back a finished response, usually HTML. The visitor never downloads your source code. Rasmus Lerdorf created PHP in 1994, and it is now developed by a global community with funding from The PHP Foundation.

<?php
$name = htmlspecialchars($_GET['name'] ?? 'guest');
echo "<p>Namaste, {$name}. Today is " . date('d M Y') . ".</p>";

Opening /hello.php?name=Asha returns a paragraph of HTML; the browser never sees the <?php code. htmlspecialchars() escapes the input so a visitor cannot inject script into the page.

• PHP runs on the server and sends a finished response.
• A file host that only stores files, without a PHP runtime, will not execute it.
• PHP is not a styling language; CSS handles appearance and JavaScript runs in the browser.

The web server accepts the HTTP request and passes PHP files to a process manager: Apache and Nginx usually use PHP-FPM, while LiteSpeed uses its own LSAPI workers (lsphp). OPcache keeps compiled scripts in memory so each request does not recompile them.

1. The browser requests /index.php.
2. The web server sees the .php extension and forwards the request to PHP-FPM or lsphp.
3. PHP loads the script (from OPcache if already compiled), runs it and queries the database if needed.
4. The output goes back through the web server to the browser.

The HTTP side is explained in what is a web server; if every request still recompiles, enable PHP OPcache.

PHP runs per request and fits ordinary shared Linux hosting, Node.js runs as a long-lived process suited to real-time connections, and Python suits applications and data work that usually need a VPS. No language wins every task; pick the one your project or CMS already uses.