What are some common pitfalls to avoid 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 avoid this, always sanitize and validate user input before using it in your application. 

// Example of sanitizing user input using the filter_var function
$name = filter_var($_POST['name'], FILTER_SANITIZE_STRING);
$email = filter_var($_POST['email'], FILTER_VALIDATE_EMAIL);
```

Another common pitfall is not handling form validation properly, which can result in unexpected behavior or errors in your application. Make sure to validate all required fields and provide appropriate error messages to the user if validation fails.

```php
// Example of form validation
if(empty($_POST['name'])) {
    $errors[] = 'Name is required';
}

if(!filter_var($_POST['email'], FILTER_VALIDATE_EMAIL)) {
    $errors[] = 'Invalid email address';
}

if(!empty($errors)) {
    foreach($errors as $error) {
        echo $error;
    }
}

Keywords

SQL injection cross-site scripting validation sanitization CSRF protection

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