Untitled

//File 1

<html>
<head>
	<title> Form</title>
</head>
<body>

	<form action="form_processing.php" method="post">
		Username: <input type="text" name="username" value=""><br/>
		password: <input type="password" name="password" value=""><br/>
		<br/>
		<input type="submit" name="submit" value="Submit">
	</form>

</body>
</html>


//File 2
<?php

	if(isset($_POST['submit'])){              	 //checks if the submit button has been pressed
		$username = $_POST['username'];
		$password = $_POST['password'];
	}else{                                           //When the submit button isn't pressed
		$username = null;
		$password = null;
	}


/*  //Alternative way to check form submission

	$username = isset($_POST['username'])?$_POST['username']: "";
	$password = isset($_POST['password'])?$_POST['password']: "";

*/
	//the following codes are interpretion of the code above.


/*	if(isset($_POST['username']))            //Detecting if the form has submitted the username value
		$username = $_POST['username'];      //Gets the username through the superglobal POST array from index.php
	else
		$username = null;           		 //Set Null as the default value when form date is not posted


	if(isset($_POST['password']))			 //Detecting if the form has submitted the password value
		$password = $_POST['password'];      //Gets the password through the superglobal POST array from index.php
	else
		$password = null;					 //Set Null as the default value when form date is not posted

*/

	echo $username."<br/>";              //prints the username
	echo $password;                      //prints the password ;) Don't recommend to do in real life

?>