This is the first page: Index.php
<?php
session_start();
?>
<!DOCTYPE html>
<html>
<head>
<title>Index</title>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
</head>
<body>
<form name="Index" action="Result.php" method="POST">
Username: <input type="text" name="username" id="username" autocomplete="off"><br><br> 1. I identify my gender as... <br>   
<input type="radio" name="gender" value="male">Male<br>   
<input type="radio" name="gender" value="female">Female<br>   
<input type="radio" name="gender" value="others">Others<br><br>
<INPUT Type="submit" Value="Proceed" Onclick="Index.action='Test2.php'; return true;">
</form>
</body>
</html>
<?php
session_destroy();
?>
This is the second page: Test2.php
<?php
session_start();
?>
<!DOCTYPE html>
<html>
<head>
<title>Test2</title>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
</head>
<body>
<form action="Result.php" method="POST">
2. What is your age?<br>   
<input type="radio" name="age" value="14years">Under 14 years old<br>   
<input type="radio" name="age" value="15years">15-24 years old<br>   
<input type="radio" name="age" value="25years">25-59 years old<br>   
<input type="radio" name="age" value="60years">60-74 years old<br>   
<input type="radio" name="age" value="75years">Above 75 years old<br><br><br><br>
<INPUT Type="submit" Value="Proceed" Onclick="Index.action='Test3.php'; return true;">
</form>
</body>
</html>
<?php
session_destroy();
?>
This is the third page: Test3.php
<?php
session_start();
?>
<!DOCTYPE html>
<html>
<head>
<title>Test3</title>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
</head>
<body>
<form action="Result.php" method="POST">
3. Please specify your ethnicity (race)<br>   
<input type="radio" name="race" value="chinese">Chinese<br>   
<input type="radio" name="race" value="malay">Malay<br>   
<input type="radio" name="race" value="indian">Indian<br>   
<input type="radio" name="race" value="others">Others<br><br>
<input type="submit" name="submit" value="Submit">
</form>
</body>
</html>
<?php
session_destroy();
?>
This is the last page: Result.php
<?php
session_start();
?>
<html>
<head>
<title>Result</title>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
</head>
<body>
Welcome!
<?php echo $_POST["username"]; ?><br>
<?php
$gender = $_POST['gender'];
if ($gender == "others")
echo "<font size='5'>You are not normal</font><br><br>";
else
echo "<font size='5'>You are normal</font><br><br>";
$age = $_POST['age'];
if (($age == "60years") || ($age == "75years"))
echo "<font size='5'>You are old man</font><br><br>";
else
echo "<font size='5'>You are young man</font><br><br>";
$race = $_POST['race'];
if ($race == "others")
echo "<font size='5'>You are from other race</font><br><br>";
else
echo "<font size='5'>You are from one of three races</font><br><br>";
?>
</body>
</html>
<?php
session_destroy();
?>
So, This is the four pages do: Index.php -> Test2.php -> Test3.php -> Result.php where Result.php displays the values of the textbox and radio buttons (if...else). But when I run the pages: Index.php go to Test2.php and just skip the Test3.php and direct go to Result.php. And in Reslt.php, I got this outcome: enter image description here
So, what should I do? I searched over the Internet and tried different solutions out there but couldn't work as I expected. After that, I discovered that there maybe has some problems with the button. So, again I go to Internet to find proper solution but failed to do so. Now I have no idea how to do that. Some explanations with code will be a big help for me. Thanks ;)