Add different class name on same navigation depends by page - php

Question

My navigation is called on all page with code <?php include 'navigation.php'; ?>. Navigation I want to use on all pages:
<nav class="white-color">
<!-- nav code -->
</nav>
But I need to change class="white-color" on specific pages to be class="black-color". Is there a option to add simple PHP code to define:
<?php
if($page == "index") {
echo '
<nav class="first-class">
</nav>
';
} else if($page == "register") {
echo '
<nav class="second-class">
</nav>
';
} else {
/* DEFAULT CLASS FOR PAGES*/
echo '
<nav class="third-class">
</nav>
';
}
?>
Or maybe I can resolve this with the switch method. Any advice or example will be good.
Thanks all for helping me.

Answer 1

basename($_SERVER['SCRIPT_FILENAME'])
will return the file name that is currently in use. So if you are on localhost/index.php it will return index.php.
Furthermore you can make your code more effective by doing the following:
print "<nav class='";
if(basename($_SERVER['SCRIPT_FILENAME']) == "index.php"){
print "first-class";
}
else if(basename($_SERVER['SCRIPT_FILENAME']) == "register.php"){
print "second-class";
}
else{
print "third-class";
}
print "'></nav>";
If we take into account the comment from deceze it would look like this.
if(basename($_SERVER['SCRIPT_FILENAME']) == "index.php"){
$navClass = "first-class";
}
else if(basename($_SERVER['SCRIPT_FILENAME']) == "register.php"){
$navClass = "second-class";
}
else{
$navClass = "third-class";
}
print "<nav class='$navClass'></nav>";