How to Run a Whole site From index.php - php

Question

I have noticed that in a couple of sites they can run the whole site from just the index.php, I also noticed the same effect in phpmyadmin to some extent.
An example of a site that does this is Try Open School, it is a demo site, and you can log in with (admin as password and admin as username, or teacher, teacher, or student, student). If you notice all that changes about the URL is the Query String.
I looked through the site and all I can Image is a whole lot of codes on just one page, But I do not think this is the case. I tried mine and I did something like this..
<?php
if($_GET['ref'] == 'home')
{
require_once("home.php");
}
elseif($_GET['ref'] == 'profile')
{
require_once("profile.php");
}
?>
I used the URL Query String to make reference to the different pages and to make other logical decisions.
I did a whole lot of this on the page, and the page contained several hundreds of if else statements. I do not know if I am doing what they did on their site.
I love the concept and would like to implement that kind of stuff on my own site.
I would appreciate all help on how to go about this. Thanks

Answer 1

If $_GET['ref'] is the only parameter for selecting page. a php switch, would probably be a better solution.
If you want to get fewer lines of code in your index file, you could put the switch in a separete php file!
Like this (index.php)
<?php
echo "<div id=header>Someinput</div>
<div id=menu>Some menu input</div>
<div id=site>";
require("switch.php");
echo "</div>
<div id=footer>Some footer input</div>";
?>
Then (switch.php):
<?php
switch($_GET['ref']){
case "page1":
include("page1.php");
break 1;
case "page2":
include("page2.php");
break 1;
default:
include("404.php");
}
?>