visibility.core.js
3 years ago
visibility.fallback.js
3 years ago
visibility.js
3 years ago
visibility.timers.js
3 years ago
visibility.core.js
190 lines
| 1 | ;(function (global) { |
| 2 | var lastId = -1; |
| 3 | |
| 4 | // Visibility.js allow you to know, that your web page is in the background |
| 5 | // tab and thus not visible to the user. This library is wrap under |
| 6 | // Page Visibility API. It fix problems with different vendor prefixes and |
| 7 | // add high-level useful functions. |
| 8 | var self = { |
| 9 | |
| 10 | // Call callback only when page become to visible for user or |
| 11 | // call it now if page is visible now or Page Visibility API |
| 12 | // doesn’t supported. |
| 13 | // |
| 14 | // Return false if API isn’t supported, true if page is already visible |
| 15 | // or listener ID (you can use it in `unbind` method) if page isn’t |
| 16 | // visible now. |
| 17 | // |
| 18 | // Visibility.onVisible(function () { |
| 19 | // startIntroAnimation(); |
| 20 | // }); |
| 21 | onVisible: function (callback) { |
| 22 | var support = self.isSupported(); |
| 23 | if ( !support || !self.hidden() ) { |
| 24 | callback(); |
| 25 | return support; |
| 26 | } |
| 27 | |
| 28 | var listener = self.change(function (e, state) { |
| 29 | if ( !self.hidden() ) { |
| 30 | self.unbind(listener); |
| 31 | callback(); |
| 32 | } |
| 33 | }); |
| 34 | return listener; |
| 35 | }, |
| 36 | |
| 37 | // Call callback when visibility will be changed. First argument for |
| 38 | // callback will be original event object, second will be visibility |
| 39 | // state name. |
| 40 | // |
| 41 | // Return listener ID to unbind listener by `unbind` method. |
| 42 | // |
| 43 | // If Page Visibility API doesn’t supported method will be return false |
| 44 | // and callback never will be called. |
| 45 | // |
| 46 | // Visibility.change(function(e, state) { |
| 47 | // Statistics.visibilityChange(state); |
| 48 | // }); |
| 49 | // |
| 50 | // It is just proxy to `visibilitychange` event, but use vendor prefix. |
| 51 | change: function (callback) { |
| 52 | if ( !self.isSupported() ) { |
| 53 | return false; |
| 54 | } |
| 55 | lastId += 1; |
| 56 | var number = lastId; |
| 57 | self._callbacks[number] = callback; |
| 58 | self._listen(); |
| 59 | return number; |
| 60 | }, |
| 61 | |
| 62 | // Remove `change` listener by it ID. |
| 63 | // |
| 64 | // var id = Visibility.change(function(e, state) { |
| 65 | // firstChangeCallback(); |
| 66 | // Visibility.unbind(id); |
| 67 | // }); |
| 68 | unbind: function (id) { |
| 69 | delete self._callbacks[id]; |
| 70 | }, |
| 71 | |
| 72 | // Call `callback` in any state, expect “prerender”. If current state |
| 73 | // is “prerender” it will wait until state will be changed. |
| 74 | // If Page Visibility API doesn’t supported, it will call `callback` |
| 75 | // immediately. |
| 76 | // |
| 77 | // Return false if API isn’t supported, true if page is already after |
| 78 | // prerendering or listener ID (you can use it in `unbind` method) |
| 79 | // if page is prerended now. |
| 80 | // |
| 81 | // Visibility.afterPrerendering(function () { |
| 82 | // Statistics.countVisitor(); |
| 83 | // }); |
| 84 | afterPrerendering: function (callback) { |
| 85 | var support = self.isSupported(); |
| 86 | var prerender = 'prerender'; |
| 87 | |
| 88 | if ( !support || prerender != self.state() ) { |
| 89 | callback(); |
| 90 | return support; |
| 91 | } |
| 92 | |
| 93 | var listener = self.change(function (e, state) { |
| 94 | if ( prerender != state ) { |
| 95 | self.unbind(listener); |
| 96 | callback(); |
| 97 | } |
| 98 | }); |
| 99 | return listener; |
| 100 | }, |
| 101 | |
| 102 | // Return true if page now isn’t visible to user. |
| 103 | // |
| 104 | // if ( !Visibility.hidden() ) { |
| 105 | // VideoPlayer.play(); |
| 106 | // } |
| 107 | // |
| 108 | // It is just proxy to `document.hidden`, but use vendor prefix. |
| 109 | hidden: function () { |
| 110 | return !!(self._doc.hidden || self._doc.webkitHidden); |
| 111 | }, |
| 112 | |
| 113 | // Return visibility state: 'visible', 'hidden' or 'prerender'. |
| 114 | // |
| 115 | // if ( 'prerender' == Visibility.state() ) { |
| 116 | // Statistics.pageIsPrerendering(); |
| 117 | // } |
| 118 | // |
| 119 | // Don’t use `Visibility.state()` to detect, is page visible, because |
| 120 | // visibility states can extend in next API versions. |
| 121 | // Use more simpler and general `Visibility.hidden()` for this cases. |
| 122 | // |
| 123 | // It is just proxy to `document.visibilityState`, but use |
| 124 | // vendor prefix. |
| 125 | state: function () { |
| 126 | return self._doc.visibilityState || |
| 127 | self._doc.webkitVisibilityState || |
| 128 | 'visible'; |
| 129 | }, |
| 130 | |
| 131 | // Return true if browser support Page Visibility API. |
| 132 | // refs: https://developer.mozilla.org/en-US/docs/Web/API/Page_Visibility_API |
| 133 | // |
| 134 | // if ( Visibility.isSupported() ) { |
| 135 | // Statistics.startTrackingVisibility(); |
| 136 | // Visibility.change(function(e, state)) { |
| 137 | // Statistics.trackVisibility(state); |
| 138 | // }); |
| 139 | // } |
| 140 | isSupported: function () { |
| 141 | return self._doc.hidden !== undefined || self._doc.webkitHidden !== undefined; |
| 142 | }, |
| 143 | |
| 144 | // Link to document object to change it in tests. |
| 145 | _doc: document || {}, |
| 146 | |
| 147 | // Callbacks from `change` method, that wait visibility changes. |
| 148 | _callbacks: { }, |
| 149 | |
| 150 | // Listener for `visibilitychange` event. |
| 151 | _change: function(event) { |
| 152 | var state = self.state(); |
| 153 | |
| 154 | for ( var i in self._callbacks ) { |
| 155 | self._callbacks[i].call(self._doc, event, state); |
| 156 | } |
| 157 | }, |
| 158 | |
| 159 | // Set listener for `visibilitychange` event. |
| 160 | _listen: function () { |
| 161 | if ( self._init ) { |
| 162 | return; |
| 163 | } |
| 164 | |
| 165 | var event = 'visibilitychange'; |
| 166 | if ( self._doc.webkitVisibilityState ) { |
| 167 | event = 'webkit' + event; |
| 168 | } |
| 169 | |
| 170 | var listener = function () { |
| 171 | self._change.apply(self, arguments); |
| 172 | }; |
| 173 | if ( self._doc.addEventListener ) { |
| 174 | self._doc.addEventListener(event, listener); |
| 175 | } else { |
| 176 | self._doc.attachEvent(event, listener); |
| 177 | } |
| 178 | self._init = true; |
| 179 | } |
| 180 | |
| 181 | }; |
| 182 | |
| 183 | if ( typeof(module) != 'undefined' && module.exports ) { |
| 184 | module.exports = self; |
| 185 | } else { |
| 186 | global.Visibility = self; |
| 187 | } |
| 188 | |
| 189 | })(this); |
| 190 |