affix.js

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


(function (o_o) {
  typeof define  === 'function' && define.amd ? define(['jquery'], o_o) :
  typeof exports === 'object' ? o_o(require('jquery')) : o_o(this.jQuery)
})(function ($) {

  'use strict';

  // AFFIX CLASS DEFINITION
  // ======================

  var Affix = function (element, options) {
    this.options = $.extend({}, Affix.DEFAULTS, options)

    this.$target = $(this.options.target)
      .on('scroll.bs.affix.data-api', $.proxy(this.checkPosition, this))
      .on('click.bs.affix.data-api',  $.proxy(this.checkPositionWithEventLoop, this))

    this.$element     = $(element)
    this.affixed      =
    this.unpin        =
    this.pinnedOffset = null

    this.checkPosition()
  }

  Affix.VERSION  = '3.1.1'

  Affix.RESET    = 'affix affix-top affix-bottom'

  Affix.DEFAULTS = {
    offset: 0,
    target: window
  }

  Affix.prototype.getPinnedOffset = function () {
    if (this.pinnedOffset) return this.pinnedOffset
    this.$element.removeClass(Affix.RESET).addClass('affix')
    var scrollTop = this.$target.scrollTop()
    var position  = this.$element.offset()
    return (this.pinnedOffset = position.top - scrollTop)
  }

  Affix.prototype.checkPositionWithEventLoop = function () {
    setTimeout($.proxy(this.checkPosition, this), 1)
  }

  Affix.prototype.checkPosition = function () {
    if (!this.$element.is(':visible')) return

    var scrollHeight = $(document).height()
    var scrollTop    = this.$target.scrollTop()
    var position     = this.$element.offset()
    var offset       = this.options.offset
    var offsetTop    = offset.top
    var offsetBottom = offset.bottom

    if (typeof offset != 'object')         offsetBottom = offsetTop = offset
    if (typeof offsetTop == 'function')    offsetTop    = offset.top(this.$element)
    if (typeof offsetBottom == 'function') offsetBottom = offset.bottom(this.$element)

    var affix = this.unpin   != null && (scrollTop + this.unpin <= position.top) ? false :