(PHP) Trying to controll the include function - php

Question

I am now done making my website dynamic (control multiple pages througe 1 page)
I have template where I have 2 side bars left and right, right for categories, left for the the many pages of each category.
Now using the include function to dynamicly generate the side bars is great,
but i am also using class:current on these side bars so the user can easily detect where he is.
now with the right sidebar there is no problem because if the user is in HTML category it will be highlighted with class:current but will not need to change, because user is still in HTML category.
but if the user switch page the left side bar will stay with the last class:current (for example html intro ), even tho user switched to next page (html basics).
i can only have 1 class:current when using the include function.
how can i controll that?
the code below is the file that im including to each page dynamicly it is .php file.
<div class="sidenav">
<h3> HTML Collection</h3>
<hr class="hr1">
<a class="current" style="cursor: pointer;" onclick="window.location.href = 'html_default.php';"> HTML Intro</a>
<a style="cursor: pointer;" onclick="window.location.href = 'html_editors.php';"> HTML Editors</a>
<a style="cursor: pointer;" onclick="window.location.href = 'html_basics.php';"> HTML Basics</a>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
</div>
<div class="sidenavright">
<h3> Categories</h3>
<hr class="hr1">
<a style="cursor: pointer;" onclick="window.location.href = '../javascript/js_intro.php';"> Javascript</a>
<hr class="hr1" />
<a class="current" style="cursor: pointer;" onclick="window.location.href = '../html/html_default.php';"> HTML</a>
<hr class="hr1" />
<a style="cursor: pointer;" onclick="window.location.href = '../howtomain/howto_default.php';"> HowTo</a>
<hr class="hr1" />
<a style="cursor: pointer;" onclick="window.location.href = '../python/python_intro.php';"> Python</a>
<hr class="hr1" />
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
</div>

Answer 1

You should be doing this all though JavaScript really, something like AngularJS, or maybe even use Laravel and it would be very easy to control it in your blade views.
Here’s something you can do however.
From the file where you are including it, define a variable before the include that will allow the include to know what page you’re on.
Like so:
$currPage = “page1”;
Then in your include, on each tag, you can programmatically put your current class on using one line if/elses, like so:
<a <?php ($currPage == “page1”) ? echo ‘class=“current”’ : echo ‘’?>>Page 1</a>
And repeat for all pages you want.
One line if/elses in PHP go like this:
Condition ? //true : //false
Good luck