empty: function() { ???????var elem, ???????????i = 0; ???????for ( ; (elem = this[i]) != null; i++ ) { ???????????// Remove element nodes and prevent memory leaks ???????????if ( elem.nodeType === 1 ) { ???????????????????????????????//循环清除Data数据 ???????????????jQuery.cleanData( getAll( elem, false ) ); ???????????} ???????????// 移除child ???????????while ( elem.firstChild ) { ???????????????elem.removeChild( elem.firstChild ); ???????????} ???????????// If this is a select, ensure that it displays empty (#12336) ???????????// Support: IE<9 ???????????if ( elem.options && jQuery.nodeName( elem, "select" ) ) { ???????????????elem.options.length = 0; ???????????} ???????} ???????return this; ???}, ???代码中，首先清除了所有的data数据，那么data都包含哪些内容呢？
getALl方法查找到到所有后代元素。jquery的getAll代码如下：
var strundefined = typeof undefined;function getAll( context, tag ) { ???var elems, elem, ???????i = 0, ???????found = typeof context.getElementsByTagName !== strundefined ? context.getElementsByTagName( tag || "*" ) : ???????????typeof context.querySelectorAll !== strundefined ? context.querySelectorAll( tag || "*" ) : ???????????undefined; ???if ( !found ) { ???????for ( found = [], elems = context.childNodes || context; (elem = elems[i]) != null; i++ ) { ???????????if ( !tag || jQuery.nodeName( elem, tag ) ) { ???????????????found.push( elem ); ???????????} else { ???????????????jQuery.merge( found, getAll( elem, tag ) ); ???????????} ???????} ???} ???return tag === undefined || tag && jQuery.nodeName( context, tag ) ? ???????jQuery.merge( [ context ], found ) : ???????found;}getAll(document.body,false);// HTMLCollection Array将getALl取到的集合， cleanData
- removeEvent 解除事件，释放内存 （jquery绑定的事件保存在data中），代码如下，可以找到我们绑定的事件列表。//expando是页面中不重复的jquery每个对象的标识。expando: "jQuery" + ( version + Math.random() ).replace( /\D/g, "" ),
$(‘body‘).on(‘click‘,function(){ ???alert(‘this is body‘);});console.log($.cache[$(‘body‘)[0][$.expando]]); - 删除internalKey（对象标识），push id到deletedIds
简单的说empty，首先循环给后代元素移除绑定、清除jquery给此dom的cache，然后循环removeFirstChild。
而html(‘‘)，则是简单暴力的设置innerHTML = ‘‘;
转自：http://www.cnblogs.com/henryli/archive/2014/02/25/3566461.html
jQuery源码之 empty与html('')的区别
原文地址：https://www.cnblogs.com/catgatp/p/9498525.html