Options +FollowSymlinks
 
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !^(.+)\.(css|js|jpg|gif|png|ico)$
RewriteRule ^(.*) index.php [QSA,L]

<?php
 
$p=explode('/',$_SERVER['REQUEST_URI']);
 
if ($p[1]=='') {
    $p[1]='index';
}
 
if (file_exists($m=$p[1].'.ctrl')) {
    ob_start();
    require $m;
    $content = ob_get_contents();
    ob_end_clean();
} 
else {
    $content = 'page not found';
}
 
include 'layout.php';

<?php
 
//reads the address and splits it with explode function
//for example, adress /article/100-Hello/4, creates $p array ['','article','100-Hello','4']
//Chosen page will be in the array element with index 1
$p=explode('/',$_SERVER['REQUEST_URI']);
 
//checks for home page with uri '/' then $p[1] will be '', if so we assign value 'index'.
if ($p[1]=='') {
    $p[1]='index';
}
 
//we check for file existence. For example files: index.ctrl, user.ctr, login.ctrl
if (file_exists($m=$p[1].'.ctrl')) {
    //if exists, we do not output it but we execute file and save output in the variable $content.
    ob_start();
    require $m;
    $content = ob_get_contents();
    ob_end_clean();
} 
else {
    //if it doesn't exist, then we save in content that page cannot be found
    $content = 'page not found';
}
 
//By now we have generated changing content of the page, we call for layout.php which will output all content including $content.
include 'layout.php';

<div>Header</div>
<?php echo $content; ?>
<div>Footer</div>

<b> You are in the home page </b>

Hi! I am <?php echo $p[2]; ?>. user.