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modal.js对应的是bs的模态框组件。该组件主要有以下特点：
并不是绝对居中于浏览器窗口，而是水平居中，同时顶部距离浏览器顶部有一定的距离，其原因是因为modal框的内容可能出现滚动，垂直居中不太可能，它没有做成模态框内部滚动的效果；
动画是通过css3的translate实现的：transform: translate(0, -25%);
遮罩层的元素不是包含在modal里面的，而是与modal元素平级，都是body元素的子元素
不支持在已弹出的modal上继续弹框，主要是遮罩层叠加的问题
该组件内部包含一些如网页宽度计算，浏览器滚动条计算的函数，有一些学习的价值
事件监听这一块写的不太合理，混杂在各个具体的方法中，而不是统一地在一处管理
以下是具体代码，解释都以注释的形式说明，bs官方给出的例子中包含的html和css，再多看几遍注释，应该能很好地理解该组件的实现：
/* ========================================================================
* Bootstrap: modal.js v3.3.4
* http://getbootstrap.com/javascript/#modals
* ========================================================================
* Copyright 2011-2015 Twitter, Inc.
* Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
* ======================================================================== */
+function ($) {
‘use strict‘;
// MODAL CLASS DEFINITION
// ======================
var Modal = function (element, options) {
this.options = options
this.$body = $(document.body)
this.$element = $(element) //.modal对应的元素
this.$dialog = this.$element.find(‘.modal-dialog‘)
this.$backdrop = null //遮罩元素，如果没有这个元素，在IE9下，被模态窗口覆盖的链接、按钮仍能继续点击
this.isShown = null
this.originalBodyPad = null //保留body元素原来的padding值
this.scrollbarWidth = 0
this.ignoreBackdropClick = false //是否忽略遮罩元素上的点击，默认的情况是点击遮罩会隐藏modal元素
//异步加载模态窗口的内容，如果通过remote配置了异步加载地址的话
if (this.options.remote) {
this.$element
.find(‘.modal-content‘)
.load(this.options.remote, $.proxy(function () {
this.$element.trigger(‘loaded.bs.modal‘)
}, this))
}
}
Modal.VERSION = ‘3.3.4‘
Modal.TRANSITION_DURATION = 300
Modal.BACKDROP_TRANSITION_DURATION = 150
Modal.DEFAULTS = {
backdrop: true,//是否需要遮罩
keyboard: true,//是否支持按esc键时隐藏模态窗口
show: true//是否在$(..).modal()的时候立即弹出模态窗口
}
Modal.prototype.toggle = function (_relatedTarget) {
return this.isShown ? this.hide() : this.show(_relatedTarget)
}
Modal.prototype.show = function (_relatedTarget) {
var that = this
var e = $.Event(‘show.bs.modal‘, { relatedTarget: _relatedTarget })
this.$element.trigger(e)
if (this.isShown || e.isDefaultPrevented()) return
this.isShown = true
this.checkScrollbar()
this.setScrollbar()
this.$body.addClass(‘modal-open‘)//设置overflow:hidden，在body元素溢出时隐藏body元素的滚动条
this.escape()
this.resize()
//模态框的关闭按钮
this.$element.on(‘click.dismiss.bs.modal‘, ‘[data-dismiss="modal"]‘, $.proxy(this.hide, this))
//点击dialog的时候不会触发hide
this.$dialog.on(‘mousedown.dismiss.bs.modal‘, function () {
that.$element.one(‘mouseup.dismiss.bs.modal‘, function (e) {
if ($(e.target).is(that.$element)) that.ignoreBackdropClick = true
})
})
//先处理遮罩元素，再调用回调显示modal元素
this.backdrop(function () {
var transition = $.support.transition && that.$element.hasClass(‘fade‘)
if (!that.$element.parent().length) {
that.$element.appendTo(that.$body) // don‘t move modals dom position
}
that.$element
.show()
.scrollTop(0)//有可能有溢出，每次弹出的时候都滚到最顶部
that.adjustDialog()
if (transition) {
that.$element[0].offsetWidth // force reflow
}
//force reflow 跟浏览器渲染有关，虽然这样会有损性能，但是如果不这么调用的话，有可能z-index的渲染会有问题，
//因为浏览器对dom处理的缓存机制
//触发动画
that.$element
.addClass(‘in‘)
.attr(‘aria-hidden‘, false)
that.enforceFocus()
var e = $.Event(‘shown.bs.modal‘, { relatedTarget: _relatedTarget })
transition ?
that.$dialog // wait for modal to slide in
.one(‘bsTransitionEnd‘, function () {
that.$element.trigger(‘focus‘).trigger(e)
})
.emulateTransitionEnd(Modal.TRANSITION_DURATION) :
that.$element.trigger(‘focus‘).trigger(e)
})
}
//关闭modal
Modal.prototype.hide = function (e) {
if (e) e.preventDefault()
e = $.Event(‘hide.bs.modal‘)
this.$element.trigger(e)
if (!this.isShown || e.isDefaultPrevented()) return
this.isShown = false
this.escape()
this.resize()
$(document).off(‘focusin.bs.modal‘)
//开始进行关闭动画，移除show的时候绑定的事件监听器
this.$element
.removeClass(‘in‘)
.attr(‘aria-hidden‘, true)
.off(‘click.dismiss.bs.modal‘)
.off(‘mouseup.dismiss.bs.modal‘)
this.$dialog.off(‘mousedown.dismiss.bs.modal‘)
$.support.transition && this.$element.hasClass(‘fade‘) ?
this.$element
.one(‘bsTransitionEnd‘, $.proxy(this.hideModal, this))
.emulateTransitionEnd(Modal.TRANSITION_DURATION) :
this.hideModal()
}
//focusin事件支持代理,focus事件不支持,enforceFocus方法的目的是
//当document捕获到focusin事件时，说明内部有元素获得了焦点
//假如这个焦点元素不在modal元素内，那么强制触发modal元素focus事件，使其获得焦点
Modal.prototype.enforceFocus = function () {
$(document)
.off(‘focusin.bs.modal‘) // guard against infinite focus loop
.on(‘focusin.bs.modal‘, $.proxy(function (e) {
if (this.$element[0] !== e.target && !this.$element.has(e.target).length) {
this.$element.trigger(‘focus‘)
}
}, this))
}
//ESC键的处理，show与hide方法都会调用
Modal.prototype.escape = function () {
if (this.isShown && this.options.keyboard) {
this.$element.on(‘keydown.dismiss.bs.modal‘, $.proxy(function (e) {
e.which == 27 && this.hide()
}, this))
} else if (!this.isShown) {
this.$element.off(‘keydown.dismiss.bs.modal‘)
}
}
//widnow resize的处理
Modal.prototype.resize = function () {
if (this.isShown) {
$(window).on(‘resize.bs.modal‘, $.proxy(this.handleUpdate, this))
} else {
$(window).off(‘resize.bs.modal‘)
}
}
Modal.prototype.hideModal = function () {
var that = this
this.$element.hide()
this.backdrop(function () {
that.$body.removeClass(‘modal-open‘)//恢复溢出
that.resetAdjustments()//取消modal元素的左右padding
that.resetScrollbar()//重置body元素的padding-right
that.$element.trigger(‘hidden.bs.modal‘)
})
}
//删除遮罩元素
Modal.prototype.removeBackdrop = function () {
this.$backdrop && this.$backdrop.remove()
this.$backdrop = null
}
//遮罩处理
Modal.prototype.backdrop = function (callback) {
var that = this
var animate = this.$element.hasClass(‘fade‘) ? ‘fade‘ : ‘‘
if (this.isShown && this.options.backdrop) {
var doAnimate = $.support.transition && animate
this.$backdrop = $(‘<div class="modal-backdrop ‘ + animate + ‘" />‘)
.appendTo(this.$body)
this.$element.on(‘click.dismiss.bs.modal‘, $.proxy(function (e) {
//如果点的是dialog就返回
if (this.ignoreBackdropClick) {
this.ignoreBackdropClick = false
return
}
if (e.target !== e.currentTarget) return
//如果options.backdrop配置不是static，那么点的空白部分时就会隐藏modal
this.options.backdrop == ‘static‘
? this.$element[0].focus()
: this.hide()
}, this))
if (doAnimate) this.$backdrop[0].offsetWidth // force reflow
this.$backdrop.addClass(‘in‘)
if (!callback) return
doAnimate ?
this.$backdrop
.one(‘bsTransitionEnd‘, callback)
.emulateTransitionEnd(Modal.BACKDROP_TRANSITION_DURATION) :
callback()
} else if (!this.isShown && this.$backdrop) {
this.$backdrop.removeClass(‘in‘)
var callbackRemove = function () {
that.removeBackdrop()
callback && callback()
}
$.support.transition && this.$element.hasClass(‘fade‘) ?
this.$backdrop
.one(‘bsTransitionEnd‘, callbackRemove)
.emulateTransitionEnd(Modal.BACKDROP_TRANSITION_DURATION) :
callbackRemove()
} else if (callback) {
callback()
}
}
// these following methods are used to handle overflowing modals
Modal.prototype.handleUpdate = function () {
this.adjustDialog()
}
//在show的时候，以及浏览器窗口调整的时候调用，目的是：
//在body溢出而modal没有溢出的时候，给modal添加padding-right
//在body没有溢出而modal溢出的时候，给modal添加padding-left
//目的还是为了让modal元素水平居中于浏览器窗口中
Modal.prototype.adjustDialog = function () {
var modalIsOverflowing = this.$element[0].scrollHeight > document.documentElement.clientHeight
this.$element.css({
paddingLeft: !this.bodyIsOverflowing && modalIsOverflowing ? this.scrollbarWidth : ‘‘,
paddingRight: this.bodyIsOverflowing && !modalIsOverflowing ? this.scrollbarWidth : ‘‘
})
}
//重置modal元素的左右padding，这主要是因为adjustDialog方法的调用，所以在hide的时候得还原
Modal.prototype.resetAdjustments = function () {
this.$element.css({
paddingLeft: ‘‘,
paddingRight: ‘‘
})
}
Modal.prototype.checkScrollbar = function () {
var fullWindowWidth = window.innerWidth
if (!fullWindowWidth) { // workaround for missing window.innerWidth in IE8
var documentElementRect = document.documentElement.getBoundingClientRect()
fullWindowWidth = documentElementRect.right - Math.abs(documentElementRect.left)
}
this.bodyIsOverflowing = document.body.clientWidth < fullWindowWidth//记录body元素是否有溢出
this.scrollbarWidth = this.measureScrollbar()//得到当前浏览器滚动条的宽度
}
//在body发生溢出的时候，给body添加padding-right。该值等于当前浏览器滚动条的宽度加上body元素原有的padding-right
//这个是在show方法调用的时候才会调的，目的是为了让modal元素完全水平居中在浏览器窗口中
Modal.prototype.setScrollbar = function () {
var bodyPad = parseInt((this.$body.css(‘padding-right‘) || 0), 10)
this.originalBodyPad = document.body.style.paddingRight || ‘‘
if (this.bodyIsOverflowing) this.$body.css(‘padding-right‘, bodyPad + this.scrollbarWidth)
}
//在hide的时候重置body元素的padding-right
Modal.prototype.resetScrollbar = function () {
this.$body.css(‘padding-right‘, this.originalBodyPad)
}
//计算当前浏览器的滚动条宽度
Modal.prototype.measureScrollbar = function () { // thx walsh
var scrollDiv = document.createElement(‘div‘)
scrollDiv.className = ‘modal-scrollbar-measure‘
this.$body.append(scrollDiv)
var scrollbarWidth = scrollDiv.offsetWidth - scrollDiv.clientWidth
this.$body[0].removeChild(scrollDiv)
return scrollbarWidth
}
// MODAL PLUGIN DEFINITION
// =======================
function Plugin(option, _relatedTarget) {
return this.each(function () {
var $this = $(this)
var data = $this.data(‘bs.modal‘)
var options = $.extend({}, Modal.DEFAULTS, $this.data(), typeof option == ‘object‘ && option)
if (!data) $this.data(‘bs.modal‘, (data = new Modal(this, options)))
if (typeof option == ‘string‘) data[option](_relatedTarget)
else if (options.show) data.show(_relatedTarget)
})
}
var old = $.fn.modal
$.fn.modal = Plugin
$.fn.modal.Constructor = Modal
// MODAL NO CONFLICT
// =================
$.fn.modal.noConflict = function () {
$.fn.modal = old
return this
}
// MODAL DATA-API
// ==============
$(document).on(‘click.bs.modal.data-api‘, ‘[data-toggle="modal"]‘, function (e) {
var $this = $(this)
var href = $this.attr(‘href‘)
var $target = $($this.attr(‘data-target‘) || (href && href.replace(/.*(?=#[^\s]+$)/, ‘‘))) // strip for ie7
var option = $target.data(‘bs.modal‘) ? ‘toggle‘ : $.extend({ remote: !/#/.test(href) && href }, $target.data(), $this.data())
if ($this.is(‘a‘)) e.preventDefault()
$target.one(‘show.bs.modal‘, function (showEvent) {
if (showEvent.isDefaultPrevented()) return // only register focus restorer if modal will actually get shown
$target.one(‘hidden.bs.modal‘, function () {
$this.is(‘:visible‘) && $this.trigger(‘focus‘)
})
})
Plugin.call($target, option, this)
})
}(jQuery);标签：
原文地址：http://my.oschina.net/lyzg/blog/494815
