<?php

$menu=array
(
"Link 1"=>array("index.php?page=seite1"),

"Link 2"=>array("index.php?page=seite2",
"Link 2a"=>"index.php?page=seite2a",
"Link 2b"=>"index.php?page=seite2b"),

"Link 3"=>array("index.php?page=seite3"),

"Link 4"=>array("index.php?page=seite4",
"Link 4a"=>"index.php?page=seite4a",
"Link 4b"=>"index.php?page=seite4b"),

"Link 5"=>array("index.php?page=seite5"),
);

$uri=basename(getenv("REQUEST_URI"));
foreach($menu as $main => $mainlink)
{
foreach($mainlink as $sub => $sublink)
{
$x=count($mainlink);
if ((empty($sub[0])) && $mainlink[0] == $uri && $x > 1)
{
echo'<ul><li>'.$main.'</li></ul>';
}
else if ((empty($sub[0])) && $mainlink[0] == $uri && $x == 1)
{
echo'<li>'.$main.'</li>';
}
else if ((empty($sub[0])) && $x > 1)
{
echo'<ul><li><a href="'.$mainlink[0].'">'.$main.'</a></li></ul>';
}
else if ((empty($sub[0])) && $x == 1)
{
echo'<li><a href="'.$mainlink[0] .'">'.$main.'</a></li>';
}
else if ($mainlink[0] == $uri)
{
echo'<ul><li><a href="'.$sublink.'">'.$sub.'</a></li></ul>';
}
if (array_search($uri,$mainlink) && (!empty($sub[0])))
{
if ($uri == $sublink)
{
echo'<ul><li>'.$sub.'</li></ul>';
}
else
{
echo'<ul><li><a href="'.$sublink.'">'.$sub.' </a></li></ul>';
}
}
}
}

?>