What are some common pitfalls when working with form data in PHP?

One common pitfall when working with form data in PHP is not properly sanitizing user input, which can lead to security vulnerabilities such as SQL injection or cross-site scripting attacks. To solve this issue, always use functions like htmlentities() or htmlspecialchars() to sanitize user input before using it in your application. 

// Example of sanitizing user input using htmlspecialchars()
$user_input = $_POST['user_input'];
$sanitized_input = htmlspecialchars($user_input);
```

Another pitfall is not validating user input before processing it, which can result in unexpected behavior or errors in your application. To avoid this, always validate user input using functions like filter_var() or regular expressions.

```php
// Example of validating user input using filter_var()
$user_email = $_POST['user_email'];
if (filter_var($user_email, FILTER_VALIDATE_EMAIL)) {
    // Process the email
} else {
    // Handle invalid email input
}

Keywords

SQL injection cross-site scripting validation sanitization CSRF protection

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