не срабатывает условие if

$(document).ready(function () { 
		  $('.sub > a').click(function(){ 
		     if ($(this).attr('class') != 'active'){ 
		       $('.sub ul').slideUp(); 
			   $(this).next().slideToggle(); 
			 } 
		      return false; 
		  }); 
		       $('.mini-menu > ul > li > a').click(function(){ 
			   $('.mini-menu > ul > li > a, .sub a').removeClass('active'); 
			   $(this).addClass('active'); 
			}), 
		       $('.sub ul li a').click(function(){ 
			   $('.sub ul li a').removeClass('active'); 
			   $(this).addClass('active'); 
			}); 
 
 
		   $('.slider_slick_items').slick({ 
		    prevArrow: '<i id="prev_arrow_slider" class="fa fa-angle-left"></i>', 
            nextArrow: '<i id="next_arrow_slider" class="fa fa-angle-right"></i>' 
		}); 
		});

php 
 
 
<?php  
$query = "SELECT * FROM categories"; 
$result = mysqli_query($link, $query) or die (mysqli_error($link)); 
for ($data = []; $row = mysqli_fetch_assoc($result); $data[] = $row); 
$content = ''; 
$tree = []; 
foreach ($data as $elem) { 
    $tree[$elem['parent_id']][] = $elem; 
} 
 
function treePrint($tree, $pid=0) { 
    if (empty($tree[$pid])) { 
        return; 
    } 
    echo '<ul>'; 
    foreach ($tree[$pid] as $k => $row) { 
        if ($row['parent_id'] == '0') { 
            $class = 'sub'; 
        } else { 
            $class = 'down_item'; 
        } 
        echo "<li class=\"$class\"><a href=\"?itemCard=$row[id]\">$row[category]</a>"; 
        if (isset($tree[$row['id']])) { 
            treePrint($tree, $row['id']); 
        } 
        echo '</li>'; 
 
    } 
    echo '</ul>'; 
 
} 
 
?> 
 
<div class="mini-menu"> 
 
    <?php  
        treePrint($tree); 
     ?> 
    
</div>