Form Handler with Validation.php

<?php
$name = $email = $message = "";
$nameErr = $emailErr = $messageErr = "";

if ($_SERVER["REQUEST_METHOD"] == "POST") {
    // Name validation
    if (empty($_POST["name"])) {
        $nameErr = "Name is required";
    } else {
        $name = test_input($_POST["name"]);
        if (!preg_match("/^[a-zA-Z ]*$/", $name)) {
            $nameErr = "Only letters and spaces are allowed";
        }
    }

    // Email validation
    if (empty($_POST["email"])) {
        $emailErr = "Email is required";
    } else {
        $email = test_input($_POST["email"]);
        if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
            $emailErr = "Invalid email format";
        }
    }

    // Message validation
    if (empty($_POST["message"])) {
        $messageErr = "Message is required";
    } else {
        $message = test_input($_POST["message"]);
    }

    // If no errors, send the email
    if (empty($nameErr) && empty($emailErr) && empty($messageErr)) {
        $to = "your-email@example.com"; // Replace with your email
        $subject = "Contact Form Submission from $name";
        $body = "Name: $name\nEmail: $email\nMessage: $message";
        $headers = "From: $email";

        if (mail($to, $subject, $body, $headers)) {
            echo "Thank you for your message!";
        } else {
            echo "There was an error sending your message.";
        }
    }
}

// Function to clean input data
function test_input($data) {
    return htmlspecialchars(stripslashes(trim($data)));
}
?>