https://www.saaten-zeller.de/templates/protostar/js/bootstrap-scrollspy.js

1/* =============================================================
2 * bootstrap-scrollspy.js v2.0.0
3 * http://twitter.github.com/bootstrap/javascript.html#scrollspy
4 * =============================================================
5 * Copyright 2012 Twitter, Inc.
6 *
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 * ============================================================== */
19
20!function ( $ ) {
21
22  "use strict"
23
24  /* SCROLLSPY CLASS DEFINITION
25   * ========================== */
26
27  function ScrollSpy( element, options) {
28    var process = $.proxy(this.process, this)
29      , $element = $(element).is('body') ? $(window) : $(element)
30      , href
31    this.options = $.extend({}, $.fn.scrollspy.defaults, options)

32    this.$scrollElement = $element.on('scroll.scroll.data-api', process)
33    this.selector = (this.options.target
34      || ((href = $(element).attr('href')) && href.replace(/.*(?=#[^\s]+$)/, '')) //strip for ie7
35      || '') + ' .nav li > a'
36    this.$body = $('body').on('click.scroll.data-api', this.selector, process)
37    this.refresh()
38    this.process()
39  }
40
41  ScrollSpy.prototype = {
42
43      constructor: ScrollSpy
44
45    , refresh: function () {
46        this.targets = this.$body
47          .find(this.selector)
48          .map(function () {
49            var href = $(this).attr('href')
50            return /^#\w/.test(href) && $(href).length ? href : null
51          })
52
53        this.offsets = $.map(this.targets, function (id) {
54          return $(id).position().top
55        })
56      }
57
58    , process: function () {
59        var scrollTop = this.$scrollElement.scrollTop() + this.options.offset
60          , offsets = this.offsets
61          , targets = this.targets
62          , activeTarget = this.activeTarget
63          , i
64
65        for (i = offsets.length; i--;) {
66          activeTarget != targets[i]
67            && scrollTop >= offsets[i]
68            && (!offsets[i + 1] || scrollTop <= offsets[i + 1])
69            && this.activate( targets[i] )
70        }
71      }
72
73    , activate: function (target) {
74        var active
75
76        this.activeTarget = target
77
78        this.$body
79          .find(this.selector).parent('.active')
80          .removeClass('active')
81
82        active = this.$body
83          .find(this.selector + '[href="' + target + '"]')
84          .parent('li')
85          .addClass('active')
86
87        if ( active.parent('.dropdown-menu') )  {
88          active.closest('li.dropdown').addClass('active')
89        }
90      }
91
92  }
93
94
95 /* SCROLLSPY PLUGIN DEFINITION
96  * =========================== */
97
98  $.fn.scrollspy = function ( option ) {
99    return this.each(function () {
100      var $this = $(this)
101        , data = $this.data('scrollspy')
102        , options = typeof option == 'object' && option
103      if (!data) $this.data('scrollspy', (data = new ScrollSpy(this, options)))
104      if (typeof option == 'string') data[option]()
105    })
106  }
107
108  $.fn.scrollspy.Constructor = ScrollSpy
109
110  $.fn.scrollspy.defaults = {
111    offset: 10
112  }
113
114
115 /* SCROLLSPY DATA-API
116  * ================== */
117
118  $(function () {
119    $('[data-spy="scroll"]').each(function () {
120      var $spy = $(this)
121      $spy.scrollspy($spy.data())
122    })
123  })
124
125}( window.jQuery )