How does the usage of $_POST differ from defining variables directly in PHP forms?

When defining variables directly in PHP forms, the values are hardcoded within the form itself. This means that the values are fixed and cannot be changed dynamically by the user. On the other hand, using $_POST allows the form data to be submitted to the server, where it can be processed and stored in variables that can be manipulated within the PHP script. 

<form method="post" action="">
  <input type="text" name="username">
  <input type="password" name="password">
  <input type="submit" value="Submit">
</form>

<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
  $username = $_POST['username'];
  $password = $_POST['password'];
  
  // Process the form data as needed
}
?>

Keywords

$_POST variables PHP forms data submission security

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