What are some common pitfalls when using PHP for form validation?

One common pitfall when using PHP for form validation is not properly sanitizing user input, leaving the application vulnerable to attacks such as SQL injection or cross-site scripting. To solve this issue, always use functions like htmlspecialchars() or mysqli_real_escape_string() to sanitize user input before using it in SQL queries or displaying it on the webpage. 

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

// Example of sanitizing user input using mysqli_real_escape_string()
$user_input = $_POST['user_input'];
$sanitized_input = mysqli_real_escape_string($connection, $user_input);

Keywords

SQL injection cross-site scripting empty fields regular expressions error handling

Related Questions