1 (
function (global) {
2 let startY = 0
3 let enabled =
false
4 let supportsPassiveOption =
false
5 try {
6 let opts = Object.defineProperty({}, 'passive'
, {
7 get:
function () {
8 supportsPassiveOption =
true
9 }
10 })
11 window.addEventListener('test',
null, opts)
12 }
catch (e) {
13 // console.log('false')
14 }
15 const handleTouchmove =
function (evt) {
16 let el =
evt.target
17 let zoom = window.innerWidth /
window.document.documentElement.clientWidth
18 if (evt.touches.length > 1 || zoom !== 1
) {
19 return
20 }
21 while (el !== document.body && el !==
document) {
22 let style =
window.getComputedStyle(el)
23 if (!
style) {
24 break
25 }
26 if (el.nodeName === 'INPUT' && el.getAttribute('type') === 'range'
) {
27 return
28 }
29 let scrolling = style.getPropertyValue('-webkit-overflow-scrolling'
)
30 let overflowY = style.getPropertyValue('overflow-y'
)
31 let height =
el.clientHeight
32 // let height = parseInt(style.getPropertyValue('height'), 10)
33 let isScrollable = scrolling === 'touch' && (overflowY === 'auto' || overflowY === 'scroll'
)
34 let canScroll = el.scrollHeight >
el.offsetHeight
35 if (isScrollable &&
canScroll) {
36 let curY = evt.touches ? evt.touches[0
].screenY : evt.screenY
37 let isAtTop = (startY <= curY && el.scrollTop === 0
)
38 let isAtBottom = (startY >= curY && el.scrollHeight - el.scrollTop ===
height)
39 if (isAtTop ||
isAtBottom) {
40 evt.preventDefault()
41 }
42 return
43 }
44 el =
el.parentNode
45 }
46 evt.preventDefault()
47 }
48 const handleTouchstart =
function (evt) {
49 startY = evt.touches ? evt.touches[0
].screenY : evt.screenY
50 }
51 const enable =
function () {
52 window.addEventListener('touchstart', handleTouchstart, supportsPassiveOption ? { passive:
false } :
false)
53 window.addEventListener('touchmove', handleTouchmove, supportsPassiveOption ? { passive:
false } :
false)
54 enabled =
true
55 }
56 const disable =
function () {
57 window.removeEventListener('touchstart', handleTouchstart,
false)
58 window.removeEventListener('touchmove', handleTouchmove,
false)
59 enabled =
false
60 }
61 const isEnabled =
function () {
62 return enabled
63 }
64 let testDiv = document.createElement('div'
)
65 document.documentElement.appendChild(testDiv)
66 testDiv.style.WebkitOverflowScrolling = 'touch'
67 let scrollSupport = 'getComputedStyle'
in window && window.getComputedStyle(testDiv)['-webkit-overflow-scrolling'] === 'touch'
68 document.documentElement.removeChild(testDiv)
69 if (scrollSupport) {
70 enable()
71 }
72 let preventOverScroll =
{
73 enable: enable,
74 disable: disable,
75 isEnabled: isEnabled
76 }
77 if (
typeof module !== 'undefined' &&
module.exports) {
78 module.exports =
preventOverScroll
79 }
80 if (
typeof global.define === 'function'
) {
81 (
function (define) {
82 define('iNoBounce', [],
function () {
83 return preventOverScroll
84 })
85 }(global.define))
86 }
else {
87 global.preventOverScroll =
preventOverScroll
88 }
89 }(
this))
转载于:https://www.cnblogs.com/QQPrincekin/p/11541211.html
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