How can PHP developers ensure data integrity and prevent data manipulation when passing values between pages?

To ensure data integrity and prevent data manipulation when passing values between pages, PHP developers can use techniques such as input validation, data sanitization, and parameterized queries. By validating and sanitizing input data, developers can ensure that only expected and safe values are passed between pages, reducing the risk of data manipulation. Additionally, using parameterized queries when interacting with databases helps prevent SQL injection attacks, further enhancing data integrity.

// Example of input validation and data sanitization
$user_input = $_POST['user_input'];

// Validate input data
if (filter_var($user_input, FILTER_VALIDATE_INT)) {
    // Sanitize input data
    $sanitized_input = filter_var($user_input, FILTER_SANITIZE_STRING);
    
    // Use sanitized input data in further processing
    // For example, storing in a database or displaying on a page
}