0
0
mirror of https://github.com/twbs/bootstrap.git synced 2024-12-04 16:24:22 +01:00
Bootstrap/docs/assets/js/bootstrap-affix.js
2012-08-21 13:11:25 -07:00

104 lines
3.1 KiB
JavaScript

/* ==========================================================
* bootstrap-affix.js v2.1.1
* http://twitter.github.com/bootstrap/javascript.html#affix
* ==========================================================
* Copyright 2012 Twitter, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* ========================================================== */
!function ($) {
"use strict"; // jshint ;_;
/* AFFIX CLASS DEFINITION
* ====================== */
var Affix = function (element, options) {
this.options = $.extend({}, $.fn.affix.defaults, options)
this.$window = $(window).on('scroll.affix.data-api', $.proxy(this.checkPosition, this))
this.$element = $(element)
this.checkPosition()
}
Affix.prototype.checkPosition = function () {
if (!this.$element.is(':visible')) return
var scrollHeight = $(document).height()
, scrollTop = this.$window.scrollTop()
, position = this.$element.offset()
, offset = this.options.offset
, offsetBottom = offset.bottom
, offsetTop = offset.top
, reset = 'affix affix-top affix-bottom'
, affix
if (typeof offset != 'object') offsetBottom = offsetTop = offset
if (typeof offsetTop == 'function') offsetTop = offset.top()
if (typeof offsetBottom == 'function') offsetBottom = offset.bottom()
affix = this.unpin != null && (scrollTop + this.unpin <= position.top) ?
false : offsetBottom != null && (position.top + this.$element.height() >= scrollHeight - offsetBottom) ?
'bottom' : offsetTop != null && scrollTop <= offsetTop ?
'top' : false
if (this.affixed === affix) return
this.affixed = affix
this.unpin = affix == 'bottom' ? position.top - scrollTop : null
this.$element.removeClass(reset).addClass('affix' + (affix ? '-' + affix : ''))
}
/* AFFIX PLUGIN DEFINITION
* ======================= */
$.fn.affix = function (option) {
return this.each(function () {
var $this = $(this)
, data = $this.data('affix')
, options = typeof option == 'object' && option
if (!data) $this.data('affix', (data = new Affix(this, options)))
if (typeof option == 'string') data[option]()
})
}
$.fn.affix.Constructor = Affix
$.fn.affix.defaults = {
offset: 0
}
/* AFFIX DATA-API
* ============== */
$(window).on('load', function () {
$('[data-spy="affix"]').each(function () {
var $spy = $(this)
, data = $spy.data()
data.offset = data.offset || {}
data.offsetBottom && (data.offset.bottom = data.offsetBottom)
data.offsetTop && (data.offset.top = data.offsetTop)
$spy.affix(data)
})
})
}(window.jQuery);