jq 21-94行 定义变量

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(function (window,undefined) {
          	
})(window);

函数自执行防止污染全局.

传入window的作用
    1. 查找变量时,window为顶层,在局部引入能节省性能?
    2.可用于压缩代码?

undefined作用
    1.某些浏览器,undefined可被修改.这是为了兼容修改的情况.

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var
	// A central reference to the root jQuery(document)
	rootjQuery,//rootjQuery = jQuery(document) 
      * 理解为document的jq对象?
	// The deferred used on DOM ready
	readyList,*老师说在dom节点时详细说

	// Support: IE9
	// For `typeof xmlNode.method` instead of `xmlNode.method !== undefined`
	core_strundefined = typeof undefined,
      *  实际上就是返回'undefined'

	// Use the correct document accordingly with window argument (sandbox)
	location = window.location,
	document = window.document,
	docElem = document.documentElement,*就是html的js对象

	// Map over jQuery in case of overwrite
	_jQuery = window.jQuery,
          *为了防jQuery全局污染冲突
	// Map over the $ in case of overwrite
	_$ = window.$,
          *为了防jQuery全局污染冲突
	// [[Class]] -> type pairs
	class2type = {},
        *用来判断类型的?
	// List of deleted data cache ids, so we can reuse them
	core_deletedIds = [],

	core_version = "2.0.3",

	// Save a reference to some core methods
	core_concat = core_deletedIds.concat,
	core_push = core_deletedIds.push,
	core_slice = core_deletedIds.slice,
	core_indexOf = core_deletedIds.indexOf,
	core_toString = class2type.toString,
	core_hasOwn = class2type.hasOwnProperty,
	core_trim = core_version.trim,
        *把数组,对象,字符串原型上的一些方法用局部变量接收,        


	// Define a local copy of jQuery
*这个就是无new构造的精髓了,另起一篇,出门左转好无new构造.
	jQuery = function( selector, context ) {
		// The jQuery object is actually just the init constructor 'enhanced'
		return new jQuery.fn.init( selector, context, rootjQuery );
	},

	// Used for matching numbers
	core_pnum = /[+-]?(?:\d*\.|)\d+(?:[eE][+-]?\d+|)/.source,

	// Used for splitting on whitespace
	core_rnotwhite = /\S+/g,

	// A simple way to check for HTML strings
	// Prioritize #id over <tag> to avoid XSS via location.hash (#9521)
	// Strict HTML recognition (#11290: must start with <)
	rquickExpr = /^(?:\s*(<[\w\W]+>)[^>]*|#([\w-]*))$/,

	// Match a standalone tag
	rsingleTag = /^<(\w+)\s*\/?>(?:<\/\1>|)$/,

	// Matches dashed string for camelizing
	rmsPrefix = /^-ms-/,
	rdashAlpha = /-([\da-z])/gi,
*上面这些正则到用的时候再回过头来看吧.
	// Used by jQuery.camelCase as callback to replace()
	fcamelCase = function( all, letter ) {
*这个all是用来干什么的?看不懂.
*http://www.cnblogs.com/kuangliu/p/4724424.html 
*这又是个大神
*这个all是用来和replace配合的.比如str.repalce(reg,fcamelCase);
*不过还是没完全理解.
		return letter.toUpperCase();
	},

	// The ready event handler and self cleanup method
	completed = function() {
		document.removeEventListener( "DOMContentLoaded", completed, false );
		window.removeEventListener( "load", completed, false );
		jQuery.ready();
	};
*这个还是另起一篇比较好.