ARTICLE AD BOX
How does PHP handle form data validation and sanitization internally, and what are the best practices to prevent security vulnerabilities such as SQL injection and XSS?
I am working on a PHP-based web application that processes user input from HTML forms. While PHP provides superglobal arrays such as $_GET, $_POST, and $_REQUEST to access form data, I am trying to understand how PHP handles this data internally and what the recommended approach is for validating and sanitizing user input before using it in an application.
Many beginner tutorials demonstrate directly accessing form values from $_POST or $_GET and inserting them into a database or displaying them on a web page. However, this approach can lead to serious security vulnerabilities such as SQL injection, cross-site scripting (XSS), and cross-site request forgery (CSRF) if input is not handled properly.
I would like a detailed explanation of:
How PHP receives and stores form data in superglobal arrays
The difference between input validation and input sanitization in PHP
When and how to use functions like filter_input(), htmlspecialchars(), and mysqli_real_escape_string()
The role of prepared statements in preventing SQL injection
Common mistakes made by beginners when handling user input in PHP
Recommended best practices for securely processing form data in modern PHP applications
