alpaca/dist/lib/bootstrap-tokenfield/docs-assets/js/affix.js

Alpaca provides the easiest and fastest way to generate interactive forms for the web and mobile devices. It runs simply as HTML5 or more elaborately using Bootstrap, jQuery Mobile or jQuery UI. Alpaca uses Handlebars to process JSON schema and provide

/* ========================================================================
 * 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 ($) {
  'use strict';

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

  var Affix = function (element, options) {
    this.options = $.extend({}, Affix.DEFAULTS, options)
    this.$window = $(window)
      .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.RESET = 'affix affix-top affix-bottom'

  Affix.DEFAULTS = {
    offset: 0
  }

  Affix.prototype.getPinnedOffset = function () {
    if (this.pinnedOffset) return this.pinnedOffset
    this.$element.removeClass(Affix.RESET).addClass('affix')
    var scrollTop = this.$window.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 = $(document).height()
    var scrollTop    = this.$window.scrollTop()
    var position     = this.$element.offset()
    var offset       = this.options.offset
    var offsetTop    = offset.top
    var offsetBottom = offset.bottom

    if (this.affixed == 'top') position.top += scrollTop

    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 :
                offsetBottom != null && (position.top + this.$element.height() >= scrollHeight - offsetBottom) ? 'bottom' :
                offsetTop    != null && (scrollTop <= offsetTop) ? 'top' : false

    if (this.affixed === affix) return
    if (this.unpin) this.$element.css('top', '')

    var affixType = 'affix' + (affix ? '-' + affix : '')
    var e         = $.Event(affixType + '.bs.affix')

    this.$element.trigger(e)

    if (e.isDefaultPrevented()) return

    this.affixed = affix
    this.unpin = affix == 'bottom' ? this.getPinnedOffset() : null

    this.$element
      .removeClass(Affix.RESET)
      .addClass(affixType)
      .trigger($.Event(affixType.replace('affix', 'affixed')))

    if (affix == 'bottom') {
      this.$element.offset({ top: scrollHeight - offsetBottom - this.$element.height() })
    }
  }


  // AFFIX PLUGIN DEFINITION
  // =======================

  var old = $.fn.affix

  $.fn.affix = function (option) {
    return this.each(function () {
      var $this   = $(this)
      var data    = $this.data('bs.affix')
      var options = typeof option == 'object' && option

      if (!data) $this.data('bs.affix', (data = new Affix(this, options)))
      if (typeof option == 'string') data[option]()
    })
  }

  $.fn.affix.Constructor = Affix


  // AFFIX NO CONFLICT
  // =================

  $.fn.affix.noConflict = function () {
    $.fn.affix = old
    return this
  }


  // AFFIX DATA-API
  // ==============

  $(window).on('load', function () {
    $('[data-spy="affix"]').each(function () {
      var $spy = $(this)
      var data = $spy.data()

      data.offset = data.offset || {}

      if (data.offsetBottom) data.offset.bottom = data.offsetBottom
      if (data.offsetTop)    data.offset.top    = data.offsetTop

      $spy.affix(data)
    })
  })

}(jQuery);