https://www.rollerfreunde.de/inc/lib/bootstrap4/js/jquery-doubletap.js?rev=143

1/*!
2 * jQuery Double Tap Plugin.
3 *
4 * Copyright (c) 2010 Raul Sanchez (http://www.appcropolis.com)
5 *
6 * Dual licensed under the MIT and GPL licenses:
7 * http://www.opensource.org/licenses/mit-license.php
8 * http://www.gnu.org/licenses/gpl.html
9 */
10 
11(function($){
12    // Determine if we on iPhone or iPad
13    var isiOS = false;
14    var agent = navigator.userAgent.toLowerCase();
15    if(agent.indexOf('iphone') >= 0 || agent.indexOf('ipad') >= 0){
16           isiOS = true;
17    }
18 
19    $.fn.doubletap = function(onDoubleTapCallback, delay,onTapCallback){
20        var eventName, action;
21        delay = delay == null? 500 : delay;
22        eventName = isiOS == true? 'touchend' : 'click';        
23 
24        $(this).bind(eventName, function(event){            
25            var now = new Date().getTime();
26            var lastTouch = $(this).data('lastTouch') || now + 1 /** the first time this will make delta a negative number */;
27            var delta = now - lastTouch;
28            clearTimeout(action);
29            if(delta<500 && delta>0){                
30                if(onDoubleTapCallback != null && typeof onDoubleTapCallback == 'function'){
31                    onDoubleTapCallback(event);
32                }
33            }else{                
34                $(this).data('lastTouch', now);
35                action = setTimeout(function(evt){
36                    if(onTapCallback != null && typeof onTapCallback == 'function'){
37                        onTapCallback(evt);
38                    }
39                    clearTimeout(action);   // clear the timeout
40                }, delay, [event]);
41            }
42            $(this).data('lastTouch', now);
43        });
44    };
45})(jQuery);