https://www.queenslibrary.org/themes/renovate/bootstrap/javascripts/bootstrap/scrollspy.js?tl8z8n

1/* ========================================================================
2 * Bootstrap: scrollspy.js v3.3.7
3 * http://getbootstrap.com/javascript/#scrollspy
4 * ========================================================================
5 * Copyright 2011-2016 Twitter, Inc.
6 * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
7 * ======================================================================== */
8
9
10+function ($) {
11  'use strict';
12
13  // SCROLLSPY CLASS DEFINITION
14  // ==========================
15
16  function ScrollSpy(element, options) {
17    this.$body          = $(document.body)
18    this.$scrollElement = $(element).is(document.body) ? $(window) : $(element)
19    this.options        = $.extend({}, ScrollSpy.DEFAULTS, options)
20    this.selector       = (this.options.target || '') + ' .nav li > a'
21    this.offsets        = []
22    this.targets        = []
23    this.activeTarget   = null
24    this.scrollHeight   = 0
25
26    this.$scrollElement.on('scroll.bs.scrollspy', $.proxy(this.process, this))
27    this.refresh()
28    this.process()
29  }
30
31  ScrollSpy.VERSION  = '3.3.7'
32
33  ScrollSpy.DEFAULTS = {
34    offset: 10
35  }
36
37  ScrollSpy.prototype.getScrollHeight = function () {
38    return this.$scrollElement[0].scrollHeight || Math.max(this.$body[0].scrollHeight, document.documentElement.scrollHeight)
39  }
40
41  ScrollSpy.prototype.refresh = function () {
42    var that          = this
43    var offsetMethod  = 'offset'
44    var offsetBase    = 0
45
46    this.offsets      = []
47    this.targets      = []
48    this.scrollHeight = this.getScrollHeight()
49
50    if (!$.isWindow(this.$scrollElement[0])) {
51      offsetMethod = 'position'
52      offsetBase   = this.$scrollElement.scrollTop()
53    }
54
55    this.$body
56      .find(this.selector)
57      .map(function () {
58        var $el   = $(this)
59        var href  = $el.data('target') || $el.attr('href')
60        var $href = /^#./.test(href) && $(href)
61
62        return ($href
63          && $href.length
64          && $href.is(':visible')
65          && [[$href[offsetMethod]().top + offsetBase, href]]) || null
66      })
67      .sort(function (a, b) { return a[0] - b[0] })
68      .each(function () {
69        that.offsets.push(this[0])
70        that.targets.push(this[1])
71      })
72  }
73
74  ScrollSpy.prototype.process = function () {
75    var scrollTop    = this.$scrollElement.scrollTop() + this.options.offset
76    var scrollHeight = this.getScrollHeight()
77    var maxScroll    = this.options.offset + scrollHeight - this.$scrollElement.height()
78    var offsets      = this.offsets
79    var targets      = this.targets
80    var activeTarget = this.activeTarget
81    var i
82
83    if (this.scrollHeight != scrollHeight) {
84      this.refresh()
85    }
86
87    if (scrollTop >= maxScroll) {
88      return activeTarget != (i = targets[targets.length - 1]) && this.activate(i)
89    }
90
91    if (activeTarget && scrollTop < offsets[0]) {
92      this.activeTarget = null
93      return this.clear()
94    }
95
96    for (i = offsets.length; i--;) {
97      activeTarget != targets[i]
98        && scrollTop >= offsets[i]
99        && (offsets[i + 1] === undefined || scrollTop < offsets[i + 1])
100        && this.activate(targets[i])
101    }
102  }
103
104  ScrollSpy.prototype.activate = function (target) {
105    this.activeTarget = target
106
107    this.clear()
108
109    var selector = this.selector +
110      '[data-target="' + target + '"],' +
111      this.selector + '[href="' + target + '"]'
112
113    var active = $(selector)
114      .parents('li')
115      .addClass('active')
116
117    if (active.parent('.dropdown-menu').length) {
118      active = active
119        .closest('li.dropdown')
120        .addClass('active')
121    }
122
123    active.trigger('activate.bs.scrollspy')
124  }
125
126  ScrollSpy.prototype.clear = function () {
127    $(this.selector)
128      .parentsUntil(this.options.target, '.active')
129      .removeClass('active')
130  }
131
132
133  // SCROLLSPY PLUGIN DEFINITION
134  // ===========================
135
136  function Plugin(option) {
137    return this.each(function () {
138      var $this   = $(this)
139      var data    = $this.data('bs.scrollspy')
140      var options = typeof option == 'object' && option
141
142      if (!data) $this.data('bs.scrollspy', (data = new ScrollSpy(this, options)))
143      if (typeof option == 'string') data[option]()
144    })
145  }
146
147  var old = $.fn.scrollspy
148
149  $.fn.scrollspy             = Plugin
150  $.fn.scrollspy.Constructor = ScrollSpy
151
152
153  // SCROLLSPY NO CONFLICT
154  // =====================
155
156  $.fn.scrollspy.noConflict = function () {
157    $.fn.scrollspy = old
158    return this
159  }
160
161
162  // SCROLLSPY DATA-API
163  // ==================
164
165  $(window).on('load.bs.scrollspy.data-api', function () {
166    $('[data-spy="scroll"]').each(function () {
167      var $spy = $(this)
168      Plugin.call($spy, $spy.data())
169    })
170  })
171
172}(jQuery);