IMCA - Web Development Using PHP

The PHP interpreter processes and runs PHP code in a step-by-step way. When you write PHP code and run it, the interpreter first reads the entire PHP file from top to bottom. It looks for PHP tags (<?php ... ?>) to know where the PHP code starts and ends. Anything outside of these tags is treated as plain text and is sent directly to the browser or output. 

Inside the PHP tags, the interpreter parses the code , which means it checks the code for correct syntax (like correct use of semicolons, parentheses, and variables). If there's a mistake like a missing semicolon or wrong variable name, it shows an error. Once the code is parsed correctly, the interpreter executes the instructions line by line — doing math, working with variables, calling functions, and interacting with databases or files if needed. 

When the script finishes running, all the output — like HTML or text — is sent back to the browser. That’s why when you visit a PHP page, you see the result of the PHP code being run on the server, not the actual PHP code itself.