I have two menu on header and in mobile device when I clicked on toggle button two menu appears but one menu appear on the top.I want to merge these two menus on one while I click on toggle button and expect to see both menu at once. I checked this topic Combining multiple Bootstrap menus into one for mobile? but don't work for me
<nav class="topmenu">
<?php
wp_nav_menu( array('menu' => 'top-menu','theme_location'=> 'topmenu','depth'=> 2,'container'=> 'div','container_class'=> 'collapse navbar-collapse navbar-ex1-collapse','fallback_cb'=>'wp_bootstrap_navwalker::fallback','walker'=> new wp_bootstrap_navwalker()));
?>
</nav>
<nav class="mainmenu">
<!-- Brand and toggle get grouped for better mobile display -->
<div>
<div class="navbar-header">
<button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-ex1-collapse">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
</div>
<?php
wp_nav_menu( array('menu' => 'main-menu','theme_location'=> 'main-menu','depth'=> 2,'container'=> 'div','container_class' => 'collapse navbar-collapse navbar-ex1-collapse', 'fallback_cb'=> 'wp_bootstrap_navwalker::fallback','walker' => new wp_bootstrap_navwalker()));
?>
</div>
</nav>