https://www.librotiralibro.it/modules/customfields/views/js/jquery-watch.js

1/**
2* jquery-watcher
3*
4*  @author    Rick Strahl
5*  @copyright © 2014-2020 Rick Strahl, West Wind Technologies 
6*  @license   MIT License http://en.wikipedia.org/wiki/MIT_License
7*  @package   jquery-watcher
8*/
9
10(function($, undefined) {
11        $.fn.watch = function(options) {
12            /// <summary>
13            /// Allows you to monitor changes in a specific
14            /// CSS property of an element by polling the value.
15            /// You can also monitor attributes (using attr_ prefix)
16            /// or property changes (using prop_ prefix).
17            /// when the value changes a function is called.
18            /// The callback is fired in the context
19            /// of the selected element (ie. this)
20            ///
21            /// Uses the MutationObserver API of the DOM and
22            /// falls back to setInterval to poll for changes
23            /// for non-compliant browsers (pre IE 11)
24            /// </summary>            
25            /// <param name="options" type="Object">
26            /// Option to set - see comments in code below.
27            /// </param>        
28            /// <returns type="jQuery" /> 
29            var opt = $.extend({
30                // CSS styles or Attributes to monitor as comma delimited list
31                // For attributes use a attr_ prefix
32                // Example: "top,left,opacity,attr_class"
33                properties: null,
34
35                // interval for 'manual polling' (IE 10 and older)            
36                interval: 100,
37
38                // a unique id for this watcher instance
39                id: "_watcher_" + new Date().getTime(),
40
41                // flag to determine whether child elements are watched            
42                watchChildren: false,
43
44                // Callback function if not passed in callback parameter   
45                callback: null
46            }, options);
47
48            return this.each(function() {
49                var el = this;
50                var el$ = $(this);
51                var fnc = function(mRec, mObs) {

52                    __watcher.call(el, opt.id, mRec, mObs);
53                };
54
55                var data = {
56                    id: opt.id,
57                    props: opt.properties.split(','),
58                    vals: [opt.properties.split(',').length],
59                    func: opt.callback, // user function
60                    fnc: fnc, // __watcher internal
61                    origProps: opt.properties,
62                    interval: opt.interval,
63                    intervalId: null
64                };
65                // store initial props and values
66                $.each(data.props, function(i) {
67                    var propName = data.props[i];
68                    if (data.props[i].startsWith('attr_'))
69                        data.vals[i] = el$.attr(propName.replace('attr_', ''));
70                    else if (propName.startsWith('prop_'))
71                        data.vals[i] = el$.prop(propName.replace('props_', ''));
72                    else
73                        data.vals[i] = el$.css(propName);
74                });
75
76                el$.data(opt.id, data);
77
78                hookChange(el$, opt.id, data);
79            });
80
81            function hookChange(element$, id, data) {
82                element$.each(function() {
83                    var el$ = $(this);
84
85                    if (window.MutationObserver) {
86                        var observer = el$.data('__watcherObserver' + opt.id);
87                        if (observer == null) {
88                            observer = new MutationObserver(data.fnc);
89                            el$.data('__watcherObserver' + opt.id, observer);
90                        }
91                        observer.observe(this, {
92                            attributes: true,
93                            subtree: opt.watchChildren,
94                            childList: opt.watchChildren,
95                            characterData: true
96                        });
97                    } else
98                        data.intervalId = setInterval(data.fnc, opt.interval);
99                });
100            }
101

102            function __watcher(id, mRec, mObs) {
103                var el$ = $(this);
104                var w = el$.data(id);
105                if (!w) return;
106                var el = this;
107
108                if (!w.func)
109                    return;
110
111                var changed = false;
112                var i = 0;
113                for (i; i < w.props.length; i++) {
114                    var key = w.props[i];
115
116                    var newVal = "";
117                    if (key.startsWith('attr_'))
118                        newVal = el$.attr(key.replace('attr_', ''));
119                    else if (key.startsWith('prop_'))
120                        newVal = el$.prop(key.replace('prop_', ''));
121                    else
122                        newVal = el$.css(key);
123
124                    if (newVal == undefined)
125                        continue;
126
127                    if (w.vals[i] != newVal) {
128                        w.vals[i] = newVal;
129                        changed = true;
130                        break;
131                    }
132                }
133                if (changed) {
134                    // unbind to avoid recursive events
135                    el$.unwatch(id);
136
137                    // call the user handler

138                    w.func.call(el, w, i, mRec, mObs);
139
140                    // rebind the events
141                    hookChange(el$, id, w);
142                }
143            }
144        }
145        $.fn.unwatch = function(id) {
146            this.each(function() {
147                var el = $(this);
148                var data = el.data(id);
149                try {
150                    if (window.MutationObserver) {
151                        var observer = el.data("__watcherObserver" + id);
152                        if (observer) {
153                            observer.disconnect();
154                            el.removeData("__watcherObserver" + id);
155                        }
156                    } else
157                        clearInterval(data.intervalId);
158                }
159                // ignore if element was already unbound
160                catch (e) {
161                }
162            });
163            return this;
164        }
165        String.prototype.startsWith = function(sub) {
166            if (sub === null || sub === undefined) return false;
167            return sub == this.substr(0, sub.length);
168        }
169    }
170)(jQuery, undefined);