newbie :a very simple $_POST is giving me an error

Well, its the first time i am writing up my own php instead of editing someone else's.

Here is the very simple code where I am asking user to input a password and then just echo it.

<form action="index.php" method="POST">
	Please enter your password: <br>
	<input type="text" name="password" /> <br>
	<input type="submit" value="Submit" />
</form>

<?php
$password= $_POST['password'];
echo $password;

?>

PHP:

And, I am getting following error:
Notice: Undefined index: password in C:\wamp\www\md5\index.php on line 8

I have read everything I possibly could but still cant figure out whats wrong?

 

TRY this

<?php
if(isset($_POST['password']))
{
   $password= $_POST['password'];
   echo $password;
}

?>

PHP:

 

<?php
if(isset($_POST['password']))
{
$password= $_POST['password'];
echo $password;
}

?>

 

If you don't want the action to happend before you have clicked the button you must use isset.

if(isset($_POST['buttonName']))
{
// Action 
}

Code (markup):

 

use isset() will do the trick. or you can set variable error_reporting(E_ALL ^ E_NOTICE); before everything