Почему всегда class="treeview active"?

Question

[Lavrov95]

<?php
                if (isset($_GET['subject'])) {
                    $subject = $_GET['subject'];
                } else {
                    $subject = '';
                } ?>
                <?php if ( $subject == 'math' || 'chemistry' || 'physics' || 'biology'|| 'history' ||'english' || 'armenian' ) { ?>
                <li class="treeview active">
                <?php } else{ ?>
                <li class="treeview ">
                    <?php } ?>
                    <a href="#">
                        <i class="fa fa-edit"></i> <span>Առարկաներ</span> <i class="fa fa-angle-left pull-right"></i>
                    </a>
                    <ul class="treeview-menu">

                        <li<?php if ($subject == 'math') { ?>
                            class="active"
                        <?php } ?>><a href="allquestions.php?subject=math&id=<?php echo $id; ?>"><i
                                        class="fa fa-circle-o"></i>Մաթեմատիկա</a></li>
                        <li<?php if ($subject == 'chemistry') { ?>
                            class="active"
                        <?php } ?>><a href="allquestions.php?subject=chemistry&id=<?php echo $id; ?>"><i
                                        class="fa fa-circle-o"></i>Քիմիա</a></li>
                        <li<?php if ($subject == 'physics') { ?>
                            class="active"
                        <?php } ?>><a href="allquestions.php?subject=physics&id=<?php echo $id; ?>"><i
                                        class="fa fa-circle-o"></i>Ֆիզիկա</a></li>
                        <li<?php if ($subject == 'biology') { ?>
                            class="active"
                        <?php } ?>><a href="allquestions.php?subject=biology&id=<?php echo $id; ?>"><i
                                        class="fa fa-circle-o"></i>Կենսաբանություն</a></li>
                        <li<?php if ($subject == 'history') { ?>
                            class="active"
                        <?php } ?>><a href="allquestions.php?subject=history&id=<?php echo $id; ?>"><i
                                        class="fa fa-circle-o"></i>Պատմություն</a></li>
                        <li<?php if ($subject == 'english') { ?>
                            class="active"
                        <?php } ?>><a href="allquestions.php?subject=english&id=<?php echo $id; ?>"><i
                                        class="fa fa-circle-o"></i>Անգլերեն</a></li>
                        <li<?php if ($subject == 'armenian') { ?>
                            class="active"
                        <?php } else { ?>
                            class=""
                        <?php } ?>><a href="allquestions.php?subject=armenian&id=<?php echo $id; ?>"><i
                                        class="fa fa-circle-o"></i>Հայերեն</a></li>
                    </ul>
                </li>

Answer 1

[Растишка]

Это чё?

if ( $subject == 'math' || 'chemistry' || 'physics' || 'biology'|| 'history' ||'english' || 'armenian' ) { ?>

Надо

<?php if (in_array($subject, ['math', 'chemistry', 'physics', 'biology', 'history', 'english', 'armenian'])) { ?>