What best practices should be followed when using $_GET variables in PHP forms to avoid errors?

When using $_GET variables in PHP forms, it is important to sanitize and validate the input to avoid security vulnerabilities and errors. One common best practice is to use PHP's filter_input() function to sanitize the input and ensure it meets the expected format. Additionally, always validate and sanitize the input before using it in your application to prevent SQL injection, cross-site scripting, and other security threats. 

// Sanitize and validate the $_GET variable
$user_id = filter_input(INPUT_GET, 'user_id', FILTER_SANITIZE_NUMBER_INT);

// Check if the user_id is valid
if ($user_id !== false) {
    // Use the sanitized user_id in your application
    echo "User ID: " . $user_id;
} else {
    // Handle invalid input
    echo "Invalid user ID";
}

Keywords

$_GET variables forms errors validation

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