$mainMenu = array (
array( "title" => "Home", "href" => "/", "menu" => null, "sel" => false )
, array( "title" => "About", "href" => "/link2", "menu" => null, "sel" => false )
, array( "title" => "Contacts", "href" => "/link3", "menu" => $prefMenu, "sel" => false )
);

<?php foreach ($mainMenu as $item) {
                if ($item['menu']) {?>
                 <li class="dropdown <?php if ($item['sel']==true) echo "active";?>">
                        <a href="#" class="dropdown-toggle" data-toggle="dropdown"><?php echo $item['title']?>
                        <b class="caret"></b></a>
                        <ul class="dropdown-menu">
                            <?php foreach ($item['menu'] as $menuInfo)
                                 echo "<li><a href='{$menuInfo['href']}'>{$menuInfo['title']}</a></li>";
                            ?>
                        </ul>
                <?php } else {
                    echo "<li><a href='{$item['href']}'>{$item['title']}</a>";
                }?>
        </li>
        <li class="divider-vertical"></li>
<?php }?>