Dynamic back button depend on reference

Is it possible to create a dynamic back button that goes back to the page you came from? For example, if it comes from cocacola.php or starwars.php, the back button should go back to the respective page.

Now I have a static back button:
<a class="back" href="cocacola.php<?php echo(isset($_GET["pageNum_WADAproducts_details"])?"?pageNum_WADAproducts_details=".intval($_GET["pageNum_WADAproducts_details"]):""); ?>#rec-<?php echo($WADAproducts_details->getColumnVal("product_id"));?>" id="BackToResults" role="button">Back
</a>

This means that I have to have a duplicate where only the link is changed, which does not seem optimal.

The cocacola.php and starwars.php looks different, so I need those to be individual.

Here is the link code from cocacola.php page:
<a href="CcMoreinfo.php? product_id=<?php echo($WADAproducts->getColumnVal("product_id")); ?>
<?php echo(isset($_GET["pageNum_WADAproducts"])?"& pageNum_WADAproducts =".intval($_GET["pageNum_WADAproducts"]):""); ?>" data-toggle="tooltip" data-placement="top" title="<?php echo($pageNum_WADAproducts->getColumnVal("product_description")); ?>">
</a>

Here is the link code from the starwars.php page:
<a href="SwMoreinfo.php?product_id=<?php echo($WADAproducts->getColumnVal("product_id")); ?>
<?php echo(isset($_GET["pageNum_WADAproducts"])?"&pageNum_WADAproducts=".intval($_GET["pageNum_WADAproducts"]):""); ?>" ><?php echo($WADAproducts->getColumnVal("product_name")); ?>
</br>
<?php echo($WADAproducts->getColumnVal("product_description")); ?>
</a>

But I want the link go to same page, not CcMoreinfo.php and SwMoreinfo.php.

Attached is a conceptual image