https://leadgenic.ru/blog/mythemeblogy3/js/breakpoints/breakpoints.js

1/*
2	Breakpoints.js
3	version 1.0
4	
5	Creates handy events for your responsive design breakpoints
6	
7	Copyright 2011 XOXCO, Inc
8	http://xoxco.com/
9
10	Documentation for this plugin lives here:
11	http://xoxco.com/projects/code/breakpoints
12	
13	Licensed under the MIT license:
14	http://www.opensource.org/licenses/mit-license.php
15
16*/
17(function($) {
18
19	var lastSize = 0;
20	var interval = null;
21
22	$.fn.resetBreakpoints = function() {
23		$(window).unbind('resize');
24		if (interval) {
25			clearInterval(interval);
26		}
27		lastSize = 0;
28	};
29	
30	$.fn.setBreakpoints = function(settings) {
31		var options = jQuery.extend({
32							distinct: true,
33							breakpoints: new Array(320,480,768,1024)
34				    	},settings);
35
36        var fireBreakpoints = function() {
37
38            var w = $(window).width();
39            var done = false;
40
41            for (var bp in options.breakpoints.sort(function(a,b) { return (b-a) })) {
42
43                // fire onEnter when a browser expands into a new breakpoint
44                // if in distinct mode, remove all other breakpoints first.
45                if (!done && w >= options.breakpoints[bp] && lastSize < options.breakpoints[bp]) {
46                    if (options.distinct) {
47                        for (var x in options.breakpoints.sort(function(a,b) { return (b-a) })) {
48                            if ($('body').hasClass('breakpoint-' + options.breakpoints[x])) {
49                                $('body').removeClass('breakpoint-' + options.breakpoints[x]);
50                                $(window).trigger('exitBreakpoint' + options.breakpoints[x]);
51                            }
52                        }
53                        done = true;
54                    }
55                    $('body').addClass('breakpoint-' + options.breakpoints[bp]);
56                    $(window).trigger('enterBreakpoint' + options.breakpoints[bp]);
57
58                }
59
60                // fire onExit when browser contracts out of a larger breakpoint
61                if (w < options.breakpoints[bp] && lastSize >= options.breakpoints[bp]) {
62                    $('body').removeClass('breakpoint-' + options.breakpoints[bp]);
63                    $(window).trigger('exitBreakpoint' + options.breakpoints[bp]);
64
65                }
66
67                // if in distinct mode, fire onEnter when browser contracts into a smaller breakpoint
68                if (
69                    options.distinct && // only one breakpoint at a time
70                        w >= options.breakpoints[bp] && // and we are in this one
71                        w < options.breakpoints[bp-1] && // and smaller than the bigger one
72                        lastSize > w && // and we contracted
73                        lastSize >0 &&  // and this is not the first time
74                        !$('body').hasClass('breakpoint-' + options.breakpoints[bp]) // and we aren't already in this breakpoint
75                    ) {
76                    $('body').addClass('breakpoint-' + options.breakpoints[bp]);
77                    $(window).trigger('enterBreakpoint' + options.breakpoints[bp]);
78
79                }
80            }
81
82            // set up for next call
83            if (lastSize != w) {
84                lastSize = w;
85            }
86        };
87
88        // fire breakpoints checking only when a window size changes
89        $(window).resize(fireBreakpoints);
90        window.g1_breakpoints_api = {
91            'fireBreakpoints': fireBreakpoints
92        };
93	};
94})(jQuery);