How does using the global keyword in PHP affect the handling of POST and GET data?

Using the global keyword in PHP allows variables to be accessed outside of the current scope, which can lead to security vulnerabilities when handling POST and GET data. It is not recommended to use the global keyword for handling user input data, as it can make the code more prone to injection attacks and manipulation. Instead, it is better to use superglobal arrays like $_POST and $_GET to access user input data in a safer and more controlled manner. 

// Avoid using global keyword for handling POST and GET data
$username = $_POST['username'];
$password = $_POST['password'];

// Use superglobal arrays for accessing user input data
$username = filter_input(INPUT_POST, 'username', FILTER_SANITIZE_STRING);
$password = filter_input(INPUT_POST, 'password', FILTER_SANITIZE_STRING);

Keywords

global keyword PHP POST data GET data variable scope

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