https://www.idaten.ne.jp/portal/common/js/dropdownmenu.js

1/* This script and many more are available free online at
2The JavaScript Source!! http://javascript.internet.com
3Created by: Konstantin Jagello | http://javascript-array.com/ */
4
5var TimeOut         = 300;
6var currentLayer    = null;
7var currentitem     = null;
8var currentLayerNum = 0;
9var noClose         = 0;
10var closeTimer      = null;
11
12function mopen(n) {
13  var l  = document.getElementById("menu"+n);
14  var mm = document.getElementById("mmenu"+n);
15	
16  if(l) {
17    mcancelclosetime();
18    l.style.visibility='visible';
19    if(currentLayer && (currentLayerNum != n))
20      currentLayer.style.visibility='hidden';
21    currentLayer = l;
22    currentitem = mm;
23    currentLayerNum = n;			
24  } else if(currentLayer) {
25    currentLayer.style.visibility='hidden';
26    currentLayerNum = 0;
27    currentitem = null;
28    currentLayer = null;
29 	}
30}
31
32function mclosetime() {
33  closeTimer = window.setTimeout(mclose, TimeOut);
34}
35
36function mcancelclosetime() {
37  if(closeTimer) {
38    window.clearTimeout(closeTimer);
39    closeTimer = null;
40  }
41}
42
43function mclose() {
44  if(currentLayer && noClose!=1)   {
45    currentLayer.style.visibility='hidden';
46    currentLayerNum = 0;
47    currentLayer = null;
48    currentitem = null;
49  } else {
50    noClose = 0;
51  }
52  currentLayer = null;
53  currentitem = null;
54}
55
56document.onclick = mclose;