In PHP, what are some common pitfalls to avoid when creating interactive elements like buttons that trigger form displays?

One common pitfall to avoid when creating interactive elements like buttons that trigger form displays is not properly sanitizing user input. This can lead to security vulnerabilities such as SQL injection attacks. To solve this, always validate and sanitize user input before using it in your PHP code.

// Example of sanitizing user input before using it in PHP code
$user_input = $_POST['user_input'];
$clean_input = filter_var($user_input, FILTER_SANITIZE_STRING);
// Now $clean_input can be safely used in your PHP code