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一、前言

这节介绍下popover弹出框)模块的源码实现。

二、源码

1、popovers.less

 //// Popovers弹出框)// --------------------------------------------------.popover {position: absolute;top: 0;left: 0;z-index: @zindex-popover;display: none;max-width: @popover-max-width;padding: 1px;// Our parent element can be arbitrary since popovers are by default inserted as a sibling of their target element.// So reset our font and text properties to avoid inheriting weird values..reset-text);font-size: @font-size-base;background-color: @popover-bg;background-clip: padding-box;border: 1px solid @popover-fallback-border-color;border: 1px solid @popover-border-color;border-radius: @border-radius-large;.box-shadow0 5px 10px rgba0,0,0,.2));// Offset the popover to account for the popover arrow&.top     { margin-top: -@popover-arrow-width; }&.right   { margin-left: @popover-arrow-width; }&.bottom  { margin-top: @popover-arrow-width; }&.left    { margin-left: -@popover-arrow-width; }}.popover-title {margin: 0; // reset heading marginpadding: 8px 14px;font-size: @font-size-base;background-color: @popover-title-bg;border-bottom: 1px solid darken@popover-title-bg, 5%);border-radius: @border-radius-large - 1) @border-radius-large - 1) 0 0;}.popover-content {padding: 9px 14px;}// Arrows//// .arrow is outer, .arrow:after is inner.popover > .arrow {&,&:after {position: absolute;display: block;width: 0;height: 0;border-color: transparent;border-style: solid;}}.popover > .arrow {border-width: @popover-arrow-outer-width;}.popover > .arrow:after {border-width: @popover-arrow-width;content: "";}.popover {&.top > .arrow {left: 50%;margin-left: -@popover-arrow-outer-width;border-bottom-width: 0;border-top-color: @popover-arrow-outer-fallback-color; // IE8 fallbackborder-top-color: @popover-arrow-outer-color;bottom: -@popover-arrow-outer-width;&:after {content: " ";bottom: 1px;margin-left: -@popover-arrow-width;border-bottom-width: 0;border-top-color: @popover-arrow-color;}}&.right > .arrow {top: 50%;left: -@popover-arrow-outer-width;margin-top: -@popover-arrow-outer-width;border-left-width: 0;border-right-color: @popover-arrow-outer-fallback-color; // IE8 fallbackborder-right-color: @popover-arrow-outer-color;&:after {content: " ";left: 1px;bottom: -@popover-arrow-width;border-left-width: 0;border-right-color: @popover-arrow-color;}}&.bottom > .arrow {left: 50%;margin-left: -@popover-arrow-outer-width;border-top-width: 0;border-bottom-color: @popover-arrow-outer-fallback-color; // IE8 fallbackborder-bottom-color: @popover-arrow-outer-color;top: -@popover-arrow-outer-width;&:after {content: " ";top: 1px;margin-left: -@popover-arrow-width;border-top-width: 0;border-bottom-color: @popover-arrow-color;}}&.left > .arrow {top: 50%;right: -@popover-arrow-outer-width;margin-top: -@popover-arrow-outer-width;border-right-width: 0;border-left-color: @popover-arrow-outer-fallback-color; // IE8 fallbackborder-left-color: @popover-arrow-outer-color;&:after {content: " ";right: 1px;border-right-width: 0;border-left-color: @popover-arrow-color;bottom: -@popover-arrow-width;}}}

2、popover.js

 /* ========================================================================* Bootstrap: popover.js v3.3.7弹出框)* http://getbootstrap.com/javascript/#popovers* ========================================================================* Copyright 2011-2016 Twitter, Inc.* Licensed under MIT https://github.com/twbs/bootstrap/blob/master/LICENSE)* ======================================================================== */+function $) {
   'use strict';// POPOVER PUBLIC CLASS DEFINITION// ===============================var Popover = function element, options) {this.init'popover', element, options)}if !$.fn.tooltip) throw new Error'Popover requires tooltip.js')Popover.VERSION  = '3.3.7'Popover.DEFAULTS = $.extend{}, $.fn.tooltip.Constructor.DEFAULTS, {placement: 'right',trigger: 'click',content: '',template: '<div class="popover" role="tooltip"><div class="arrow"></div><h3 class="popover-title"></h3><div class="popover-content"></div></div>'})// NOTE: POPOVER EXTENDS tooltip.js// ================================Popover.prototype = $.extend{}, $.fn.tooltip.Constructor.prototype)Popover.prototype.constructor = PopoverPopover.prototype.getDefaults = function ) {return Popover.DEFAULTS}Popover.prototype.setContent = function ) {var $tip    = this.tip)var title   = this.getTitle)var content = this.getContent)$tip.find'.popover-title')[this.options.html ? 'html' : 'text']title)$tip.find'.popover-content').children).detach).end)[ // we use append for html objects to maintain js eventsthis.options.html ? typeof content == 'string' ? 'html' : 'append') : 'text']content)$tip.removeClass'fade top bottom left right in')// IE8 doesn't accept hiding via the `:empty` pseudo selector, we have to do// this manually by checking the contents.if !$tip.find'.popover-title').html)) $tip.find'.popover-title').hide)}Popover.prototype.hasContent = function ) {return this.getTitle) || this.getContent)}Popover.prototype.getContent = function ) {var $e = this.$elementvar o  = this.optionsreturn $e.attr'data-content')|| typeof o.content == 'function' ?o.content.call$e[0]) :o.content)}Popover.prototype.arrow = function ) {return this.$arrow = this.$arrow || this.tip).find'.arrow'))}// POPOVER PLUGIN DEFINITION// =========================function Pluginoption) {return this.eachfunction ) {var $this   = $this)var data    = $this.data'bs.popover')var options = typeof option == 'object' && optionif !data && /destroy|hide/.testoption)) returnif !data) $this.data'bs.popover', data = new Popoverthis, options)))if typeof option == 'string') data[option])})}var old = $.fn.popover$.fn.popover             = Plugin$.fn.popover.Constructor = Popover// POPOVER NO CONFLICT// ===================$.fn.popover.noConflict = function ) {$.fn.popover = oldreturn this}}jQuery);

三、应用 & 源码分析

1、应用

 <button type="button" class="btnbtn-default" data-container="body" data-placement="bottom" data-toggle="popover"data-original-title="Bootstrap弹出框标题" data-content="Bootstrap弹出框的内容">猛击我吧</button><a href="#" class="btnbtn-default" data-container="body" data-placement="right" data-toggle="popover"title="Bootstrap弹出框标题" data-content="Bootstrap弹出框的内容">猛击我吧</a>// 不能直接通过自定义属性data-来触发，需依赖于JavaScript<script type="text/javascript">$function ) {$'[data-toggle="popover"]').popover);});</script>

2、源码分析

2.1、popovers.less

1、弹出框 popover 模板与 tooltip 不同，不仅有标题，还可以设置内容

2.2、popover.js

1、popover 继承了 tooltip 的原型，只不过覆盖了部分布局方法
2、提示框 tooltip 的默认触发事件是 hover 和 focus，而弹出框 popover 是 click