1/* ========================================================== 2 * bootstrap-affix.js v2.3.1 3 * http://twitter.github.com/bootstrap/javascript.html#affix 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 21!function ($) { 22 23 "use strict"; // jshint ;_; 24 25 26 /* AFFIX CLASS DEFINITION 27 * ====================== */ 28 29 var Affix = function (element, options) { 30 this.options = $.extend({}, $.fn.affix.defaults, options) 31 this.$window = $(window) 32 .on('scroll.affix.data-api', $.proxy(this.checkPosition, this)) 33 .on('click.affix.data-api', $.proxy(function () { setTimeout($.proxy(this.checkPosition, this), 1) }, this)) 34 this.$element = $(element) 35 this.checkPosition() 36 } 37 38 Affix.prototype.checkPosition = function () { 39 if (!this.$element.is(':visible')) return 40 41 var scrollHeight = $(document).height() 42 , scrollTop = this.$window.scrollTop() 43 , position = this.$element.offset() 44 , offset = this.options.offset 45 , offsetBottom = offset.bottom 46 , offsetTop = offset.top 47 , reset = 'affix affix-top affix-bottom' 48 , affix 49 50 if (typeof offset != 'object') offsetBottom = offsetTop = offset 51 if (typeof offsetTop == 'function') offsetTop = offset.top() 52 if (typeof offsetBottom == 'function') offsetBottom = offset.bottom() 53 54 affix = this.unpin != null && (scrollTop + this.unpin <= position.top) ? 55 false : offsetBottom != null && (position.top + this.$element.height() >= scrollHeight - offsetBottom) ? 56 'bottom' : offsetTop != null && scrollTop <= offsetTop ? 57 'top' : false 58 59 if (this.affixed === affix) return 60 61 this.affixed = affix 62 this.unpin = affix == 'bottom' ? position.top - scrollTop : null 63 64 this.$element.removeClass(reset).addClass('affix' + (affix ? '-' + affix : '')) 65 } 66 67 68 /* AFFIX PLUGIN DEFINITION 69 * ======================= */ 70 71 var old = $.fn.affix 72 73 $.fn.affix = function (option) { 74 return this.each(function () { 75 var $this = $(this) 76 , data = $this.data('affix') 77 , options = typeof option == 'object' && option 78 if (!data) $this.data('affix', (data = new Affix(this, options))) 79 if (typeof option == 'string') data[option]() 80 }) 81 } 82 83 $.fn.affix.Constructor = Affix 84 85 $.fn.affix.defaults = { 86 offset: 0 87 } 88 89 90 /* AFFIX NO CONFLICT 91 * ================= */ 92 93 $.fn.affix.noConflict = function () { 94 $.fn.affix = old 95 return this 96 } 97 98 99 /* AFFIX DATA-API 100 * ============== */ 101 102 $(window).on('load', function () { 103 $('[data-spy="affix"]').each(function () { 104 var $spy = $(this) 105 , data = $spy.data() 106 107 data.offset = data.offset || {} 108 109 data.offsetBottom && (data.offset.bottom = data.offsetBottom) 110 data.offsetTop && (data.offset.top = data.offsetTop) 111 112 $spy.affix(data) 113 }) 114 }) 115 116 117}(window.jQuery);