apply-to.html

<ul id="menu-header" class="nav menu">
	<li id="menu-item-4" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-4">
		<a href="http://minecraft.nfreader.net/wordpress/">Index</a>
	</li>
	<li id="menu-item-49" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-49">
		<a href="http://minecraft.nfreader.net/wordpress/?page_id=36">Rules and other Info</a>
	</li>
	<li id="menu-item-8" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-8">
		<a href="http://minecraft.nfreader.net/wordpress/?page_id=6">Status</a>
	</li>
	<li id="menu-item-27" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-27">
		<a href="http://minecraft.nfreader.net/wordpress/?page_id=15">Maps</a>
	</li>
	<li id="menu-item-79" class="dropdown">
		<a href="#" class="dropdown-toggle" data-toggle="dropdown">Infrastructure</a>
		<ul class="dropdown-menu">
			<li id="menu-item-74" class="menu-item menu-item-type-post_type menu-item-object-page current-menu-item page_item first-page-item last-page-item page-item-68 current_page_item menu-item-74">
				<a href="http://minecraft.nfreader.net/wordpress/?page_id=68">Overview</a>
			</li>
			<li id="menu-item-75" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-75">
				<a href="http://minecraft.nfreader.net/wordpress/?page_id=72">HTA Railroad</a>
			</li>
			<li id="menu-item-76" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-76">
				<a href="http://minecraft.nfreader.net/wordpress/?page_id=70">MTG</a>
			</li>
		</ul>
	</li>
</ul>

functions.php

function add_dropdowns($output) {
    $output= preg_replace('/class="sub-menu"/', 'class="dropdown-menu"', $output, 1);
    $output= preg_replace('/id="menu-item-79"/', 'id="menu-item-79" class="dropdown"', $output, 1);
   	$output= preg_replace('/href="#"/', 'href="#" class="dropdown-toggle" data-toggle="dropdown"', $output, 1);
    return $output;
}
add_filter('wp_nav_menu', 'add_dropdowns');