What are common mistakes when handling form submissions in PHP?

One common mistake when handling form submissions in PHP is not properly sanitizing user input, which can leave your application vulnerable to SQL injection attacks. To solve this issue, always sanitize user input using functions like htmlspecialchars() or mysqli_real_escape_string() before using it in database queries. 

// Sanitize user input before using it in a database query
$username = htmlspecialchars($_POST['username']);
$email = htmlspecialchars($_POST['email']);

// Connect to the database
$connection = mysqli_connect('localhost', 'username', 'password', 'database');

// Prepare and execute the query using sanitized user input
$query = "INSERT INTO users (username, email) VALUES ('$username', '$email')";
mysqli_query($connection, $query);

Keywords

validation sanitization CSRF error handling injection

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