https://onnaturemagazine.com/wp-content/plugins/otw-sidebar-widget-manager/js/jquery.sticky.js

1// Sticky Plugin v1.0.0 for jQuery
2// =============
3// Author: Anthony Garand
4// Improvements by German M. Bravo (Kronuz) and Ruud Kamphuis (ruudk)
5// Improvements by Leonardo C. Daronco (daronco)
6// Created: 2/14/2011
7// Date: 2/12/2012
8// Website: http://labs.anthonygarand.com/sticky
9// Description: Makes an element on the page stick on the screen as you scroll
10//       It will only set the 'top' and 'position' of your element, you
11//       might need to adjust the width in some cases.
12
13(function($) {
14  var defaults = {
15      topSpacing: 0,
16      bottomSpacing: 0,
17      className: 'is-sticky',
18      wrapperClassName: 'sticky-wrapper',
19      center: false,
20      getWidthFrom: '',
21      responsiveWidth: false
22    },
23    $window = $(window),
24    $document = $(document),
25    sticked = [],
26    windowHeight = $window.height(),
27    scroller = function() {
28      var scrollTop = $window.scrollTop(),
29        documentHeight = $document.height(),
30        dwh = documentHeight - windowHeight,
31        extra = (scrollTop > dwh) ? dwh - scrollTop : 0;
32
33      for (var i = 0; i < sticked.length; i++) {
34        var s = sticked[i],
35          elementTop = s.stickyWrapper.offset().top,
36          etse = elementTop - s.topSpacing - extra;
37
38        if (scrollTop <= etse) {
39          if (s.currentTop !== null) {
40            s.stickyElement
41              .css('width', '')
42              .css('position', '')
43              .css('top', '');
44            s.stickyElement.trigger('sticky-end', [s]).parent().removeClass(s.className);
45            s.currentTop = null;
46          }
47        }
48        else {
49          var newTop = documentHeight - s.stickyElement.outerHeight()
50            - s.topSpacing - s.bottomSpacing - scrollTop - extra;
51          if (newTop < 0) {
52            newTop = newTop + s.topSpacing;
53          } else {
54            newTop = s.topSpacing;
55          }
56          if (s.currentTop != newTop) {
57            s.stickyElement
58              .css('width', s.stickyElement.width())
59              .css('position', 'fixed')
60              .css('top', newTop);
61
62            if (typeof s.getWidthFrom !== 'undefined') {
63              s.stickyElement.css('width', $(s.getWidthFrom).width());
64            }
65
66            s.stickyElement.trigger('sticky-start', [s]).parent().addClass(s.className);
67            s.currentTop = newTop;
68          }
69        }
70      }
71    },
72    resizer = function() {
73      windowHeight = $window.height();
74
75      for (var i = 0; i < sticked.length; i++) {
76        var s = sticked[i];
77        if (typeof s.getWidthFrom !== 'undefined' && s.responsiveWidth === true) {
78          s.stickyElement.css('width', $(s.getWidthFrom).width());
79        }
80      }
81    },
82    methods = {
83      init: function(options) {
84        var o = $.extend({}, defaults, options);
85        return this.each(function() {
86          var stickyElement = $(this);
87
88          var stickyId = stickyElement.attr('id');
89          var wrapperId = stickyId ? stickyId + '-' + defaults.wrapperClassName : defaults.wrapperClassName 
90          var wrapper = $('<div></div>')
91            .attr('id', stickyId + '-sticky-wrapper')
92            .addClass(o.wrapperClassName);
93          stickyElement.wrapAll(wrapper);
94
95          if (o.center) {
96            stickyElement.parent().css({width:stickyElement.outerWidth(),marginLeft:"auto",marginRight:"auto"});
97          }
98
99          if (stickyElement.css("float") == "right") {
100            stickyElement.css({"float":"none"}).parent().css({"float":"right"});
101          }
102
103          var stickyWrapper = stickyElement.parent();
104          stickyWrapper.css('height', stickyElement.outerHeight());
105          sticked.push({
106            topSpacing: o.topSpacing,
107            bottomSpacing: o.bottomSpacing,
108            stickyElement: stickyElement,
109            currentTop: null,
110            stickyWrapper: stickyWrapper,
111            className: o.className,
112            getWidthFrom: o.getWidthFrom,
113            responsiveWidth: o.responsiveWidth
114          });
115        });
116      },
117      update: scroller,
118      unstick: function(options) {
119        return this.each(function() {
120          var unstickyElement = $(this);
121
122          var removeIdx = -1;
123          for (var i = 0; i < sticked.length; i++)
124          {
125            if (sticked[i].stickyElement.get(0) == unstickyElement.get(0))
126            {
127                removeIdx = i;
128            }
129          }
130          if(removeIdx != -1)
131          {
132            sticked.splice(removeIdx,1);
133            unstickyElement.unwrap();
134            unstickyElement.removeAttr('style');
135          }
136        });
137      }
138    };
139
140  // should be more efficient than using $window.scroll(scroller) and $window.resize(resizer):
141  if (window.addEventListener) {
142    window.addEventListener('scroll', scroller, false);
143    window.addEventListener('resize', resizer, false);
144  } else if (window.attachEvent) {
145    window.attachEvent('onscroll', scroller);
146    window.attachEvent('onresize', resizer);
147  }
148
149  $.fn.sticky = function(method) {
150    if (methods[method]) {
151      return methods[method].apply(this, Array.prototype.slice.call(arguments, 1));
152    } else if (typeof method === 'object' || !method ) {
153      return methods.init.apply( this, arguments );
154    } else {
155      $.error('Method ' + method + ' does not exist on jQuery.sticky');
156    }
157  };
158
159  $.fn.unstick = function(method) {
160    if (methods[method]) {
161      return methods[method].apply(this, Array.prototype.slice.call(arguments, 1));
162    } else if (typeof method === 'object' || !method ) {
163      return methods.unstick.apply( this, arguments );
164    } else {
165      $.error('Method ' + method + ' does not exist on jQuery.sticky');
166    }
167
168  };
169  $(function() {
170    setTimeout(scroller, 0);
171  });
172})(jQuery);