functions.php

<?php

/**
 * Mobile Menu
 *
 */
function be_mobile_menu() {
	if( !class_exists( 'Walker_Nav_Menu_Dropdown' ) )
		return;
		
	wp_nav_menu( array(
		'theme_location' => 'mobile',
		'depth'          => 1,
		'walker'         => new Walker_Nav_Menu_Dropdown(),
		'items_wrap'     => '<div class="mobile-menu"><form><select onchange="if (this.value) window.location.href=this.value"><option value="">Go To&hellip;</option>%3$s</select></form></div>',
	) );	
}
add_action( 'genesis_before_header', 'be_mobile_menu' );