What are the best practices for handling user input from dropdown menus in PHP forms?

When handling user input from dropdown menus in PHP forms, it is important to validate and sanitize the input to prevent security vulnerabilities such as SQL injection or cross-site scripting attacks. One approach is to use PHP's filter_input function to sanitize and validate the input data. Additionally, always make sure to properly escape the user input before using it in database queries or outputting it to the browser. 

// Retrieve and sanitize user input from a dropdown menu
$user_input = filter_input(INPUT_POST, 'dropdown_menu', FILTER_SANITIZE_STRING);

// Escape the user input before using it in a database query
$escaped_input = mysqli_real_escape_string($connection, $user_input);

// Use the sanitized and escaped input in your application
// For example, insert into a database
$query = "INSERT INTO table_name (column_name) VALUES ('$escaped_input')";
mysqli_query($connection, $query);

Keywords

validation sanitization htmlspecialchars select form handling

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