Obfuscation / PHP JavaScript

Scipt complet 

    <style>
    .transf:hover {
    text-decoration: underline;
    cursor: pointer;
    }
    </style> 

   <script type="text/javascript">
    document.addEventListener("DOMContentLoaded", function(event) {
     var classname = document.getElementsByClassName("transf");
     for (var i = 0; i < classname.length; i++) {
     classname[i].addEventListener('click', myFunction, false);
     }
    });
    
    var myFunction = function(event) {
     var attribute = this.getAttribute("data-int");               
     document.location.href= decodeURIComponent(window.atob(attribute));        
     };
    </script> 

    <h1>Tester le lien :</h1>
    <?php
    $Lien_cache = 'ma-page-redirigee.php';                       
    ?>
    
    <br />
    <br />
    <a class="transf btn" data-int="<?php echo base64_encode($Lien_cache); ?>"> >> Tester</a>
    <br />
    <br />