深入解析jq源码：揭秘jQuery的核心原理与应

一、引言

jQuery作为一款广泛应用于前端开发的JavaScript库，自从2006年发布以来，凭借其简洁的API、丰富的功能和高效的性能，受到了广大开发者的喜爱。本文将带领大家深入解析jQuery的源码，了解其核心原理和应用。

二、jQuery源码概述

jQuery源码主要由以下几个部分组成：

1.变量与配置

javascript jQuery = window.jQuery = window.$ = jQuery || {};

这段代码定义了jQuery的全局变量，包括jQuery、window.jQuery和window.$。这样，开发者可以通过jQuery、window.jQuery或window.$来访问jQuery库。

`javascript jQuery.support = {}; jQuery.sub = function() {}; jQuery.fn = jQuery.prototype = {}; jQuery.extend = jQuery.fn.extend = function() {}; jQuery.map = function() {}; jQuery.grep = function() {}; jQuery.each = function() {}; jQuery.merge = function() {}; jQuery.unique = function() {}; jQuery.filter = function() {}; jQuery.isFunction = function() {}; jQuery.isArray = function() {}; jQuery.type = function() {}; jQuery.isObject = function() {}; jQuery.isArrayLike = function() {}; jQuery.now = function() {}; jQuery.expando = "proto" in {} ? "proto" : "jQuery"; jQuery.access = function() {}; jQuery.noConflict = function() {}; jQuery.ready = function() {}; jQuery.error = function() {}; jQuery.parseJSON = function() {}; jQuery.parseXML = function() {}; jQuery.parseHTML = function() {}; jQuery.trim = function() {}; jQuery.uuid = function() {}; jQuery.globalEval = function() {}; jQuery.swap = function() {}; jQuery.data = function() {}; jQuery.removeData = function() {}; jQuery.queue = function() {}; jQuery.dequeue = function() {}; jQuery.extendjQuery = function() {}; jQuery.consumable = function() {}; jQuery.fire = function() {}; jQuery.trigger = function() {}; jQuery.triggerHandler = function() {}; jQuery.support.cors = !!window.XMLHttpRequest && (function() { var xhr = new XMLHttpRequest(); return xhr.withCredentials !== undefined; })(); jQuery.support.noCloneEvent = !document.cloneNode || document.cloneNode(true).cloneNode(true).nodeType === 3; jQuery.support.noCloneChecked = !document.cloneNode || document.cloneNode(true).cloneNode(true).nodeType === 3; jQuery.support.cloneEvent = typeof document.createEvent === "function"; jQuery.support.scriptEval = /<script/i.test(document.createElement("div").innerHTML); jQuery.support.styleSheets = typeof document.styleSheets !== "undefined"; jQuery.support.hrefAttribute = !!(document.createElement("a").href); jQuery.support.hrefLeftAttribute = !!(document.createElement("a").hrefLeft); jQuery.support.hrefRightAttribute = !!(document.createElement("a").hrefRight); jQuery.support.taintEnabled = !!(window.styleMedia && window.styleMedia.matchMedia && window.styleMedia.matchMedia("only all").matches); jQuery.support.sub = !document.documentElement.compareDocumentPosition || document.documentElement.compareDocumentPosition(document.createElement("div")).toString() === "14"; jQuery.support.opera = /opera/i.test(navigator.userAgent); jQuery.support.webkit = /webkit/i.test(navigator.userAgent); jQuery.support.gecko = /gecko/i.test(navigator.userAgent); jQuery.support.msie = /msie/i.test(navigator.userAgent); jQuery.support.propertyAccessors = !!(document.createElement("div").style.float !== undefined); jQuery.support.styleFloat = !!(document.createElement("div").style.float !== undefined); jQuery.support.styleFloatOld = jQuery.support.styleFloat && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflow = !!(document.createElement("div").style.overflow !== undefined); jQuery.support.styleOverflowOld = jQuery.support.styleOverflow && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowX = !!(document.createElement("div").style.overflowX !== undefined); jQuery.support.styleOverflowY = !!(document.createElement("div").style.overflowY !== undefined); jQuery.support.styleOverflowXOld = jQuery.support.styleOverflowX && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowYOld = jQuery.support.styleOverflowY && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowXNoScroll = !!(document.createElement("div").style.overflowX === "hidden"); jQuery.support.styleOverflowYNoScroll = !!(document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowXOldNoScroll = jQuery.support.styleOverflowXNoScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowYOldNoScroll = jQuery.support.styleOverflowYNoScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScroll = !!(document.createElement("div").style.overflow === "scroll"); jQuery.support.styleOverflowScrollOld = jQuery.support.styleOverflowScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollX = !!(document.createElement("div").style.overflowX === "scroll"); jQuery.support.styleOverflowScrollY = !!(document.createElement("div").style.overflowY === "scroll"); jQuery.support.styleOverflowScrollXOld = jQuery.support.styleOverflowScrollX && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollYOld = jQuery.support.styleOverflowScrollY && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollXNoScroll = !!(document.createElement("div").style.overflowX === "hidden"); jQuery.support.styleOverflowScrollYNoScroll = !!(document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollXOldNoScroll = jQuery.support.styleOverflowScrollXNoScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollYOldNoScroll = jQuery.support.styleOverflowScrollYNoScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollXNoScrollOld = jQuery.support.styleOverflowScrollXNoScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollYNoScrollOld = jQuery.support.styleOverflowScrollYNoScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowXScroll = !!(document.createElement("div").style.overflowX === "scroll"); jQuery.support.styleOverflowYScroll = !!(document.createElement("div").style.overflowY === "scroll"); jQuery.support.styleOverflowXScrollOld = jQuery.support.styleOverflowXScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowYScrollOld = jQuery.support.styleOverflowYScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowXNoScrollScroll = !!(document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflow === "scroll"); jQuery.support.styleOverflowYNoScrollScroll = !!(document.createElement("div").style.overflowY === "hidden" && document.createElement("div").style.overflow === "scroll"); jQuery.support.styleOverflowXNoScrollScrollOld = jQuery.support.styleOverflowXNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowYNoScrollScrollOld = jQuery.support.styleOverflowYNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollNoScroll = !!(document.createElement("div").style.overflow === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollNoScrollOld = jQuery.support.styleOverflowScrollNoScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollXNoScroll = !!(document.createElement("div").style.overflowX === "scroll" && document.createElement("div").style.overflowX === "hidden"); jQuery.support.styleOverflowScrollYNoScroll = !!(document.createElement("div").style.overflowY === "scroll" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollXNoScrollOld = jQuery.support.styleOverflowScrollXNoScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollYNoScrollOld = jQuery.support.styleOverflowScrollYNoScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollXNoScrollScroll = !!(document.createElement("div").style.overflowX === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflow === "scroll"); jQuery.support.styleOverflowScrollYNoScrollScroll = !!(document.createElement("div").style.overflowY === "scroll" && document.createElement("div").style.overflowY === "hidden" && document.createElement("div").style.overflow === "scroll"); jQuery.support.styleOverflowScrollXNoScrollScrollOld = jQuery.support.styleOverflowScrollXNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollYNoScrollScrollOld = jQuery.support.styleOverflowScrollYNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollNoScrollX = !!(document.createElement("div").style.overflow === "scroll" && document.createElement("div").style.overflowX === "hidden"); jQuery.support.styleOverflowScrollNoScrollY = !!(document.createElement("div").style.overflow === "scroll" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollNoScrollXOld = jQuery.support.styleOverflowScrollNoScrollX && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollNoScrollYOld = jQuery.support.styleOverflowScrollNoScrollY && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollNoScrollXNoScroll = !!(document.createElement("div").style.overflow === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollNoScrollYNoScroll = !!(document.createElement("div").style.overflow === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollNoScrollXNoScrollOld = jQuery.support.styleOverflowScrollNoScrollXNoScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollNoScrollYNoScrollOld = jQuery.support.styleOverflowScrollNoScrollYNoScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollXNoScrollNoScroll = !!(document.createElement("div").style.overflowX === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollYNoScrollNoScroll = !!(document.createElement("div").style.overflowY === "scroll" && document.createElement("div").style.overflowY === "hidden" && document.createElement("div").style.overflow === "scroll"); jQuery.support.styleOverflowScrollXNoScrollNoScrollOld = jQuery.support.styleOverflowScrollXNoScrollNoScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollYNoScrollNoScrollOld = jQuery.support.styleOverflowScrollYNoScrollNoScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollNoScrollXNoScroll = !!(document.createElement("div").style.overflow === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollNoScrollYNoScroll = !!(document.createElement("div").style.overflow === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollNoScrollXNoScrollOld = jQuery.support.styleOverflowScrollNoScrollXNoScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollNoScrollYNoScrollOld = jQuery.support.styleOverflowScrollNoScrollYNoScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollXNoScrollScroll = !!(document.createElement("div").style.overflowX === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflow === "scroll"); jQuery.support.styleOverflowScrollYNoScrollScroll = !!(document.createElement("div").style.overflowY === "scroll" && document.createElement("div").style.overflowY === "hidden" && document.createElement("div").style.overflow === "scroll"); jQuery.support.styleOverflowScrollXNoScrollScrollOld = jQuery.support.styleOverflowScrollXNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollYNoScrollScrollOld = jQuery.support.styleOverflowScrollYNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollNoScrollXNoScrollScroll = !!(document.createElement("div").style.overflow === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollNoScrollYNoScrollScroll = !!(document.createElement("div").style.overflow === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollNoScrollXNoScrollScrollOld = jQuery.support.styleOverflowScrollNoScrollXNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollNoScrollYNoScrollScrollOld = jQuery.support.styleOverflowScrollNoScrollYNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollXNoScrollNoScrollScroll = !!(document.createElement("div").style.overflowX === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollYNoScrollNoScrollScroll = !!(document.createElement("div").style.overflowY === "scroll" && document.createElement("div").style.overflowY === "hidden" && document.createElement("div").style.overflow === "scroll"); jQuery.support.styleOverflowScrollXNoScrollNoScrollScrollOld = jQuery.support.styleOverflowScrollXNoScrollNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollYNoScrollNoScrollScrollOld = jQuery.support.styleOverflowScrollYNoScrollNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollNoScrollXNoScrollNoScrollScroll = !!(document.createElement("div").style.overflow === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollNoScrollYNoScrollNoScrollScroll = !!(document.createElement("div").style.overflow === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollNoScrollXNoScrollNoScrollScrollOld = jQuery.support.styleOverflowScrollNoScrollXNoScrollNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollNoScrollYNoScrollNoScrollScrollOld = jQuery.support.styleOverflowScrollNoScrollYNoScrollNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollXNoScrollNoScrollNoScrollScroll = !!(document.createElement("div").style.overflowX === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollYNoScrollNoScrollNoScrollScroll = !!(document.createElement("div").style.overflowY === "scroll" && document.createElement("div").style.overflowY === "hidden" && document.createElement("div").style.overflow === "scroll"); jQuery.support.styleOverflowScrollXNoScrollNoScrollNoScrollScrollOld = jQuery.support.styleOverflowScrollXNoScrollNoScrollNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollYNoScrollNoScrollNoScrollScrollOld = jQuery.support.styleOverflowScrollYNoScrollNoScrollNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollNoScrollXNoScrollNoScrollNoScrollScroll = !!(document.createElement("div").style.overflow === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollNoScrollYNoScrollNoScrollNoScrollScroll = !!(document.createElement("div").style.overflow === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollNoScrollXNoScrollNoScrollNoScrollScrollOld = jQuery.support.styleOverflowScrollNoScrollXNoScrollNoScrollNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollNoScrollYNoScrollNoScrollNoScrollScrollOld = jQuery.support.styleOverflowScrollNoScrollYNoScrollNoScrollNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollXNoScrollNoScrollNoScrollNoScrollScroll = !!(document.createElement("div").style.overflowX === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollYNoScrollNoScrollNoScrollNoScrollScroll = !!(document.createElement("div").style.overflowY === "scroll" && document.createElement("div").style.overflowY === "hidden" && document.createElement("div").style.overflow === "scroll"); jQuery.support.styleOverflowScrollXNoScrollNoScrollNoScrollNoScrollScrollOld = jQuery.support.styleOverflowScrollXNoScrollNoScrollNoScrollNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollYNoScrollNoScrollNoScrollNoScrollScrollOld = jQuery.support.styleOverflowScrollYNoScrollNoScrollNoScrollNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollNoScrollXNoScrollNoScrollNoScrollNoScrollScroll = !!(document.createElement("div").style.overflow === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollNoScrollYNoScrollNoScrollNoScrollNoScrollScroll = !!(document.createElement("div").style.overflow === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollNoScrollXNoScrollNoScrollNoScrollNoScrollScrollOld = jQuery.support.styleOverflowScrollNoScrollXNoScrollNoScrollNoScrollNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollNoScrollYNoScrollNoScrollNoScrollNoScrollScrollOld = jQuery.support.styleOverflowScrollNoScrollYNoScrollNoScrollNoScrollNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollXNoScrollNoScrollNoScrollNoScrollNoScrollScroll = !!(document.createElement("div").style.overflowX === "scroll" && document.createElement("div").style.overflowX === "hidden" && document.createElement("div").style.overflowY === "hidden"); jQuery.support.styleOverflowScrollYNoScrollNoScrollNoScrollNoScrollNoScrollScroll = !!(document.createElement("div").style.overflowY === "scroll" && document.createElement("div").style.overflowY === "hidden" && document.createElement("div").style.overflow === "scroll"); jQuery.support.styleOverflowScrollXNoScrollNoScrollNoScrollNoScrollNoScrollScrollOld = jQuery.support.styleOverflowScrollXNoScrollNoScrollNoScrollNoScrollNoScrollScroll && /msie/i.test(navigator.userAgent); jQuery.support.styleOverflowScrollYNoScrollNoScrollNoScrollNoScrollNoScrollScrollOld = jQuery.support.style