This document provides an introduction to PHP, including:
- PHP is an open source scripting language suited for web development that can be embedded into HTML. Code is placed between <?php ?> tags.
- PHP files are processed by the web server, which returns plain HTML with no PHP code visible. Variables can store and pass different types of data between PHP sections.
- Functions allow common or repetitive tasks to be reused. Popular PHP functions and a large library are available online.
- Form data can be captured with PHP variables like $_POST then inserted into a MySQL database using SQL queries. The data is later retrieved and output dynamically.
- Data validation is important for security. Functions like htmlentities() and mysql