function ScrollSpy(element, options) {
var process = $.proxy(this.process, this)
, $element = $(element).is('body') ? $(window) : $(element)
, href
this.options = $.extend({}, $.fn.scrollspy.defaults, options)
this.$scrollElement = $element.on('scroll.scroll-spy.data-api', process)
this.selector = (this.options.target
|| ((href = $(element).attr('href')) && href.replace(/.*(?=#[^\s]+$)/, '')) //strip for ie7
|| '') + ' .nav li > a'
this.$body = $('body')
this.refresh()
this.process()
}
ScrollSpy.prototype = {
constructor: ScrollSpy
, refresh: function () {
var self = this
this.offsets = $([])
this.targets = $([])
this.$body
.find(this.selector)
.map(function () {
var $el = $(this)
, href = $el.data('target') || $el.attr('href')
, $href = /^#\w/.test(href) && $(href)
return ( $href
&& $href.length
&& [[ $href.position().top + (!$.isWindow(self.$scrollElement.get(0)) && self.$scrollElement.scrollTop()), href ]] ) || null
})
.sort(function (a, b) { return a[0] - b[0] })
.each(function () {
self.offsets.push(this[0])
self.targets.push(this[1])
})
}
, process: function () {
var scrollTop = this.$scrollElement.scrollTop() + this.options.offset
, scrollHeight = this.$scrollElement[0].scrollHeight || this.$body[0].scrollHeight
, maxScroll = scrollHeight - this.$scrollElement.height()
, offsets = this.offsets
, targets = this.targets
, activeTarget = this.activeTarget
, i
if (scrollTop >= maxScroll) {
return activeTarget != (i = targets.last()[0])
&& this.activate ( i )
}
for (i = offsets.length; i--;) {
activeTarget != targets[i]
&& scrollTop >= offsets[i]
&& (!offsets[i + 1] || scrollTop <= offsets[i + 1])
&& this.activate( targets[i] )
}
}
, activate: function (target) {
var active
, selector
this.activeTarget = target
$(this.selector)
.parent('.active')
.removeClass('active')
selector = this.selector
+ '[data-target="' + target + '"],'
+ this.selector + '[href="' + target + '"]'
active = $(selector)
.parent('li')
.addClass('active')
if (active.parent('.dropdown-menu').length) {
active = active.closest('li.dropdown').addClass('active')
}
active.trigger('activate')
}
}