https://teltow-stadtfest.de/files/js/dropdown.js?v=87660a2f

1/**
2 * Adds and removes classes to a list of links to allow keyboard accessibility
3 *
4 * @param string dropDownId
5 * @param string hoverClass
6 * @param int mouseOffDelay
7 */
8function dropdown(dropdownId, hoverClass, mouseOffDelay) {
9	if(dropdown = document.getElementById(dropdownId)) {
10		var listItems = dropdown.getElementsByTagName('li');
11		for(var i = 0; i < listItems.length; i++) {
12			listItems[i].onmouseover = function() { this.className = addClass(this); }
13			listItems[i].onmouseout = function() {
14				var that = this;
15				setTimeout(function() { that.className = removeClass(that); }, mouseOffDelay);
16				this.className = that.className;
17			}
18			
19			var anchor = listItems[i].getElementsByTagName('*');
20			anchor = anchor[0];
21			anchor.onfocus = function() { tabOn(this.parentNode); }
22			anchor.onblur = function() { tabOff(this.parentNode); }
23		}
24	}
25	
26	function tabOn(li) {
27		if(li.nodeName == 'LI') {
28			li.className = addClass(li);
29			tabOn(li.parentNode.parentNode);
30		}
31	}
32	
33	function tabOff(li) {
34		if(li.nodeName == 'LI') {
35			li.className = removeClass(li);
36			tabOff(li.parentNode.parentNode);
37		}
38	}
39	
40	function addClass(li) { return li.className + ' ' + hoverClass; }
41	function removeClass(li) { return li.className.replace(hoverClass, ""); }
42}