In order to display the dropdown menu while hover the nav, I add some scripts like this:

		function isMobile(){

			if (navigator.userAgent.match(/Android/i) || navigator.userAgent.indexOf('iPhone') != -1 || navigator.userAgent.indexOf('iPod') != -1 || navigator.userAgent.indexOf('iPad') != -1) {

				return true;

			}

			else {

				return false;

			}

		}	

	

		$(function(){

	

			if(!isMobile()) {

				$(document).off('click.bs.dropdown.data-api');

				$('li.dropdown').mouseover(function() {

					$(this).addClass('open');

				}).mouseout(function() {

					$(this).removeClass('open');

				});

			}

			

		});

It may need some style:

li.dropdown.open .dropdown-menu{display:block;}