What is the importance of server-side validation in PHP form handling?

Server-side validation in PHP form handling is important because it ensures that the data submitted by the user is valid and safe before processing it further. This helps prevent malicious attacks such as SQL injection, cross-site scripting, and form spam. By validating user input on the server side, you can provide a better user experience by giving immediate feedback on any errors in the form submission. 

// Server-side validation example
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $name = $_POST["name"];
    $email = $_POST["email"];

    // Validate name
    if (empty($name)) {
        $errors[] = "Name is required";
    }

    // Validate email
    if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
        $errors[] = "Invalid email format";
    }

    // If no errors, process the form data
    if (empty($errors)) {
        // Process form data
    } else {
        // Display errors to the user
        foreach ($errors as $error) {
            echo $error . "<br>";
        }
    }
}

Keywords

server-side validation PHP form handling security data integrity error handling

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