<?php
if ($_SERVER["REQUEST_METHOD"] == "GET" && isset($_GET["name"])) {
$name = htmlspecialchars($_GET["name"]);
echo "Hello, $name!";
}
?>
<!DOCTYPE html>
<html>
<body>
<form method="get">
Name: <input type="text" name="name">
<input type="submit" value="Submit">
</form>
</body>
</html>