https://www.jf-eiriz.pt/frontend/plugins/sticky/jquery.sticky.js

1// Sticky Plugin v1.0.3 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: 02/14/2011
7// Date: 07/20/2015
8// Website: http://stickyjs.com/
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 (factory) {
14    if (typeof define === 'function' && define.amd) {
15        // AMD. Register as an anonymous module.
16        define(['jquery'], factory);
17    } else if (typeof module === 'object' && module.exports) {
18        // Node/CommonJS
19        module.exports = factory(require('jquery'));
20    } else {
21        // Browser globals
22        factory(jQuery);
23    }
24}(function ($) {
25    var slice = Array.prototype.slice; // save ref to original slice()
26    var splice = Array.prototype.splice; // save ref to original slice()
27
28  var defaults = {
29      topSpacing: 0,
30      bottomSpacing: 0,
31      className: 'is-sticky',
32      wrapperClassName: 'sticky-wrapper',
33      center: false,
34      getWidthFrom: '',
35      widthFromWrapper: true, // works only when .getWidthFrom is empty
36      responsiveWidth: false
37    },
38    $window = $(window),
39    $document = $(document),
40    sticked = [],
41    windowHeight = $window.height(),
42    scroller = function() {
43      var scrollTop = $window.scrollTop(),
44        documentHeight = $document.height(),
45        dwh = documentHeight - windowHeight,
46        extra = (scrollTop > dwh) ? dwh - scrollTop : 0;
47
48      for (var i = 0, l = sticked.length; i < l; i++) {
49        var s = sticked[i],
50          elementTop = s.stickyWrapper.offset().top,
51          etse = elementTop - s.topSpacing - extra;
52
53        //update height in case of dynamic content
54        s.stickyWrapper.css('height', s.stickyElement.outerHeight());
55
56        if (scrollTop <= etse) {
57          if (s.currentTop !== null) {
58            s.stickyElement
59              .css({
60                'width': '',
61                'position': '',
62                'top': ''
63              });
64            s.stickyElement.parent().removeClass(s.className);
65            s.stickyElement.trigger('sticky-end', [s]);
66            s.currentTop = null;
67          }
68        }
69        else {
70          var newTop = documentHeight - s.stickyElement.outerHeight()
71            - s.topSpacing - s.bottomSpacing - scrollTop - extra;
72          if (newTop < 0) {
73            newTop = newTop + s.topSpacing;
74          } else {
75            newTop = s.topSpacing;
76          }
77          if (s.currentTop !== newTop) {
78            var newWidth;
79            if (s.getWidthFrom) {
80                newWidth = $(s.getWidthFrom).width() || null;
81            } else if (s.widthFromWrapper) {
82                newWidth = s.stickyWrapper.width();
83            }
84            if (newWidth == null) {
85                newWidth = s.stickyElement.width();
86            }
87            s.stickyElement
88              .css('width', newWidth)
89              .css('position', 'fixed')
90              .css('top', newTop);
91
92            s.stickyElement.parent().addClass(s.className);
93
94            if (s.currentTop === null) {
95              s.stickyElement.trigger('sticky-start', [s]);
96            } else {
97              // sticky is started but it have to be repositioned
98              s.stickyElement.trigger('sticky-update', [s]);
99            }
100
101            if (s.currentTop === s.topSpacing && s.currentTop > newTop || s.currentTop === null && newTop < s.topSpacing) {
102              // just reached bottom || just started to stick but bottom is already reached
103              s.stickyElement.trigger('sticky-bottom-reached', [s]);
104            } else if(s.currentTop !== null && newTop === s.topSpacing && s.currentTop < newTop) {
105              // sticky is started && sticked at topSpacing && overflowing from top just finished
106              s.stickyElement.trigger('sticky-bottom-unreached', [s]);
107            }
108
109            s.currentTop = newTop;
110          }
111
112          // Check if sticky has reached end of container and stop sticking
113          var stickyWrapperContainer = s.stickyWrapper.parent();
114          var unstick = (s.stickyElement.offset().top + s.stickyElement.outerHeight() >= stickyWrapperContainer.offset().top + stickyWrapperContainer.outerHeight()) && (s.stickyElement.offset().top <= s.topSpacing);
115
116          if( unstick ) {
117            s.stickyElement
118              .css('position', 'absolute')
119              .css('top', '')
120              .css('bottom', 0);
121          } else {
122            s.stickyElement
123              .css('position', 'fixed')
124              .css('top', newTop)
125              .css('bottom', '');
126          }
127        }
128      }
129    },
130    resizer = function() {
131      windowHeight = $window.height();
132
133      for (var i = 0, l = sticked.length; i < l; i++) {
134        var s = sticked[i];
135        var newWidth = null;
136        if (s.getWidthFrom) {
137            if (s.responsiveWidth) {
138                newWidth = $(s.getWidthFrom).width();
139            }
140        } else if(s.widthFromWrapper) {
141            newWidth = s.stickyWrapper.width();
142        }
143        if (newWidth != null) {
144            s.stickyElement.css('width', newWidth);
145        }
146      }
147    },
148    methods = {
149      init: function(options) {
150        var o = $.extend({}, defaults, options);
151        return this.each(function() {
152          var stickyElement = $(this);
153
154          var stickyId = stickyElement.attr('id');
155          var stickyHeight = stickyElement.outerHeight();
156          var wrapperId = stickyId ? stickyId + '-' + defaults.wrapperClassName : defaults.wrapperClassName;
157          var wrapper = $('<div></div>')
158            .attr('id', wrapperId)
159            .addClass(o.wrapperClassName);
160
161          stickyElement.wrapAll(wrapper);
162
163          var stickyWrapper = stickyElement.parent();
164
165          if (o.center) {
166            stickyWrapper.css({width:stickyElement.outerWidth(),marginLeft:"auto",marginRight:"auto"});
167          }
168
169          if (stickyElement.css("float") === "right") {
170            stickyElement.css({"float":"none"}).parent().css({"float":"right"});
171          }
172
173          stickyWrapper.css('height', stickyHeight);
174
175          o.stickyElement = stickyElement;
176          o.stickyWrapper = stickyWrapper;
177          o.currentTop    = null;
178
179          sticked.push(o);
180        });
181      },
182      update: scroller,
183      unstick: function(options) {
184        return this.each(function() {
185          var that = this;
186          var unstickyElement = $(that);
187
188          var removeIdx = -1;
189          var i = sticked.length;
190          while (i-- > 0) {
191            if (sticked[i].stickyElement.get(0) === that) {
192                splice.call(sticked,i,1);
193                removeIdx = i;
194            }
195          }
196          if(removeIdx !== -1) {
197            unstickyElement.unwrap();
198            unstickyElement
199              .css({
200                'width': '',
201                'position': '',
202                'top': '',
203                'float': ''
204              })
205            ;
206          }
207        });
208      }
209    };
210
211  // should be more efficient than using $window.scroll(scroller) and $window.resize(resizer):
212  if (window.addEventListener) {
213    window.addEventListener('scroll', scroller, false);
214    window.addEventListener('resize', resizer, false);
215  } else if (window.attachEvent) {
216    window.attachEvent('onscroll', scroller);
217    window.attachEvent('onresize', resizer);
218  }
219
220  $.fn.sticky = function(method) {
221    if (methods[method]) {
222      return methods[method].apply(this, slice.call(arguments, 1));
223    } else if (typeof method === 'object' || !method ) {
224      return methods.init.apply( this, arguments );
225    } else {
226      $.error('Method ' + method + ' does not exist on jQuery.sticky');
227    }
228  };
229
230  $.fn.unstick = function(method) {
231    if (methods[method]) {
232      return methods[method].apply(this, slice.call(arguments, 1));
233    } else if (typeof method === 'object' || !method ) {
234      return methods.unstick.apply( this, arguments );
235    } else {
236      $.error('Method ' + method + ' does not exist on jQuery.sticky');
237    }
238  };
239  $(function() {
240    setTimeout(scroller, 0);
241  });
242}));