in javascript/affix.js [29:36]
var Affix = function (element, options) {
this.options = $.extend({}, $.fn.affix.defaults, options)
this.$window = $(window)
.on('scroll.affix.data-api', $.proxy(this.checkPosition, this))
.on('click.affix.data-api', $.proxy(function () { setTimeout($.proxy(this.checkPosition, this), 1) }, this))
this.$element = $(element)
this.checkPosition()
}