Are there any best practices for handling client-side information in PHP applications?

When handling client-side information in PHP applications, it is important to validate and sanitize user input to prevent security vulnerabilities such as SQL injection and cross-site scripting attacks. One best practice is to use PHP functions like htmlspecialchars() and mysqli_real_escape_string() to sanitize input before processing it in your application.

// Example of sanitizing user input in PHP
$userInput = $_POST['user_input'];
$cleanInput = htmlspecialchars(mysqli_real_escape_string($connection, $userInput));
// Use $cleanInput in your application to prevent security vulnerabilities