web/themes/dropdownmenus/js/topnav.js

/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements.  See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License.  You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
function handleTopNav(e) {
	var resptest = document.getElementById('rightmenubox');
	if(getComputedStyle(resptest, null).display == 'none') {
		document.getElementById('site-navigation').style.position = 'relative';
		return;
	}
	var test = document.getElementById('above-site-navigation');
	var nav = document.getElementById('site-navigation');
	var box = test.getBoundingClientRect();
	var pos = nav.style.position;
	var btop = box.y;
	if(typeof(btop) === 'undefined' && typeof(box.top) !== 'undefined')
		btop = box.top;
	if(btop < 0) {
		nav.style.position = 'fixed';
	}
	else {
		nav.style.position = 'relative';
	}
}

window.addEventListener('scroll', handleTopNav, 0);