scrollspy.js

/* ========================================================================
 * Bootstrap: scrollspy.js v3.1.1
 * http://getbootstrap.com/javascript/#scrollspy
 * ========================================================================
 * Copyright 2011-2014 Twitter, Inc.
 * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
 * ======================================================================== */


+function ($) {
  'use strict';

  // SCROLLSPY CLASS DEFINITION
  // ==========================

  function ScrollSpy(element, options) {
    var href
    var process  = $.proxy(this.process, this)

    this.$element       = $(element).is('body') ? $(window) : $(element)
    this.$body          = $('body')
    this.$scrollElement = this.$element.on('scroll.bs.scrollspy', process)
    this.options        = $.extend({}, ScrollSpy.DEFAULTS, options)
    this.selector       = (this.options.target
      || ((href = $(element).attr('href')) && href.replace(/.*(?=#[^\s]+$)/, '')) //strip for ie7
      || '') + ' .nav li > a'
    this.offsets        = $([])
    this.targets        = $([])
    this.activeTarget   = null

    this.refresh()
    this.process()
  }

  ScrollSpy.DEFAULTS = {
    offset: 10
  }

  ScrollSpy.prototype.refresh = function () {
    var offsetMethod = this.$element[0] == window ? 'offset' : 'position'

    this.offsets = $([])
    this.targets = $([])

    var self     = this

    this.$body
      .find(this.selector)
      .filter(':visible')
      .map(function () {
        var $el   = $(this)
        var href  = $el.data('target') || $el.attr('href')
        var $href = /^#./.test(href) && $(href)

        return ($href
          && $href.length
          && $href.is(':visible')
          && [[ $href[offsetMethod]().top + (!$.isWindow(self.$scrollElement.get(0)) && self.$scrollElement.scrollTop()), href ]]) || null
      })
      .sort(function (a, b) { return a[0] - b[0] })
      .each(function () {
        self.offsets.push(this[0])
        self.targets.push(this[1])
      })
  }

  ScrollSpy.prototype.process = function () {
    var scrollTop    = this.$scrollElement.scrollTop() + this.options.offset
    var scrollHeight = this.$scrollElement[0].scrollHeight || Math.max(this.$body[0].scrollHeight, document.documentElement.scrollHeight)
    var maxScroll    = scrollHeight - this.$scrollElement.height()