code corrected. http://php.flashwebhost.com/mini/login_1.php

Code:
 <?php

if (isset($_GET['blood_group'])) {
     echo '<h1> Hello ' . $_GET['name'] . ' . Your Blood Group is , ' .  $_GET['blood_group'] . '! Welcome to Rotary Blood Bank.</h1>' ;
} else {

echo '
<html>
<body>

<h1>Welcome to Blood Donation Group.</h1>

<p>Please enter you name  and blood group below and click that button to enter website.</p>

<form method="GET" action="login_1.php">
    Enter Your Name: <input name="name" type="text">  <br> <br>
    Enter Your Blood Gourp : <input name="blood_group" type="text">
    <button type="submit">Enter Web Site</button>
</form>

</body>
</html>';

}