https://www.dimensionesuonosoft.it/wp-content/themes/rds-soft/js/inobounce.js

1/*! iNoBounce - v0.1.6
2* https://github.com/lazd/iNoBounce/
3* Copyright (c) 2013 Larry Davis <[email protected]>; Licensed BSD */
4(function(global) {
5	// Stores the Y position where the touch started
6	var startY = 0;
7
8	// Store enabled status
9	var enabled = false;
10
11	var supportsPassiveOption = false;
12	try {
13		var opts = Object.defineProperty({}, 'passive', {
14			get: function() {
15				supportsPassiveOption = true;
16			}
17		});
18		window.addEventListener('test', null, opts);
19	} catch (e) {}
20
21	var handleTouchmove = function(evt) {
22		// Get the element that was scrolled upon
23		var el = evt.target;
24
25		// Check all parent elements for scrollability
26		while (el !== document.body && el !== document) {
27			// Get some style properties
28			var style = window.getComputedStyle(el);
29
30			if (!style) {
31				// If we've encountered an element we can't compute the style for, get out
32				break;
33			}
34
35			// Ignore range input element
36			if (el.nodeName === 'INPUT' && el.getAttribute('type') === 'range') {
37				return;
38			}
39
40			var scrolling = style.getPropertyValue('-webkit-overflow-scrolling');
41			var overflowY = style.getPropertyValue('overflow-y');
42			var height = parseInt(style.getPropertyValue('height'), 10);
43
44			// Determine if the element should scroll
45			var isScrollable = scrolling === 'touch' && (overflowY === 'auto' || overflowY === 'scroll');
46			var canScroll = el.scrollHeight > el.offsetHeight;
47
48			if (isScrollable && canScroll) {
49				// Get the current Y position of the touch
50				var curY = evt.touches ? evt.touches[0].screenY : evt.screenY;
51
52				// Determine if the user is trying to scroll past the top or bottom
53				// In this case, the window will bounce, so we have to prevent scrolling completely
54				var isAtTop = (startY <= curY && el.scrollTop === 0);
55				var isAtBottom = (startY >= curY && el.scrollHeight - el.scrollTop === height);
56
57				// Stop a bounce bug when at the bottom or top of the scrollable element
58				if (isAtTop || isAtBottom) {
59					evt.preventDefault();
60				}
61
62				// No need to continue up the DOM, we've done our job
63				return;
64			}
65
66			// Test the next parent
67			el = el.parentNode;
68		}
69
70		// Stop the bouncing -- no parents are scrollable
71		evt.preventDefault();
72	};
73
74	var handleTouchstart = function(evt) {
75		// Store the first Y position of the touch
76		startY = evt.touches ? evt.touches[0].screenY : evt.screenY;
77	};
78
79	var enable = function() {
80		// Listen to a couple key touch events
81		window.addEventListener('touchstart', handleTouchstart, supportsPassiveOption ? { passive : false } : false);
82		window.addEventListener('touchmove', handleTouchmove, supportsPassiveOption ? { passive : false } : false);
83		enabled = true;
84	};
85
86	var disable = function() {
87		// Stop listening
88		window.removeEventListener('touchstart', handleTouchstart, false);
89		window.removeEventListener('touchmove', handleTouchmove, false);
90		enabled = false;
91	};
92
93	var isEnabled = function() {
94		return enabled;
95	};
96
97	// Enable by default if the browser supports -webkit-overflow-scrolling
98	// Test this by setting the property with JavaScript on an element that exists in the DOM
99	// Then, see if the property is reflected in the computed style
100	var testDiv = document.createElement('div');
101	document.documentElement.appendChild(testDiv);
102	testDiv.style.WebkitOverflowScrolling = 'touch';
103	var scrollSupport = 'getComputedStyle' in window && window.getComputedStyle(testDiv)['-webkit-overflow-scrolling'] === 'touch';
104	document.documentElement.removeChild(testDiv);
105
106	if (scrollSupport) {
107		enable();
108	}
109
110	// A module to support enabling/disabling iNoBounce
111	var iNoBounce = {
112		enable: enable,
113		disable: disable,
114		isEnabled: isEnabled
115	};
116
117	if (typeof module !== 'undefined' && module.exports) {
118		// Node.js Support
119		module.exports = iNoBounce;
120	}
121	if (typeof global.define === 'function') {
122		// AMD Support
123		(function(define) {
124			define('iNoBounce', [], function() { return iNoBounce; });
125		}(global.define));
126	}
127	else {
128		// Browser support
129		global.iNoBounce = iNoBounce;
130	}
131}(this));