php

<?php 

define('DISALLOW_FILE_EDIT', true);

echo "\n DISALLOW_FILE_EDIT is: " . constant('DISALLOW_FILE_EDIT') . "\n";

//$constants = get_defined_constants();
//var_dump($constants); // pretty large list
?>

Key words: define defined constant constants

$currentpage = $_SERVER['REQUEST_URI'];
if( $currentpage == "/" ) {

}

CodeIgniter is a PHP framework that will help you create web applications and web sites faster than writing code from scratch.

Login system

http://mfikri.com/en/blog/codeigniter-login

https://www.codexworld.com/codeigniter-user-registration-login-system/