var a = { name: 123}; var b = a; a.name; 123 b.name; 123 a.name = ‘wolf‘; "wolf" b.name "wolf" a.name = null; //注销此引用对象的内存，引用此引用对象的对象，失去对引用对象的引用，获得属于自己的引用对象副本; null b.name null a = null; null b Object {name: null}
原文：http://www.cnblogs.com/juhualang/p/3936040.html