<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <script type=text/javascript charset=utf-8> var x = "x"; var y = "yyy"; function F(a){ this.n = ‘fsfsf‘; this.sc = 4; var i = new init(this);//F()，this指的是window i.ii = "ii"; } function init(o){ alert(o);//[object Window] alert(sc);//4 alert(o.x);//x alert(o.y);//yyy this.n = o.sc; //init方法不是对象调用的时候，new的时候this指的是本类的对象，不是window对象 this.name = "namename"; this.o = o; that = this; return function(){ alert("333" + this.n);//undefined,this是这个匿名函数的对象 alert("333" + that.n); this.h = that; this.k = that.n; this.a = that.a } ; } alert(1); var d = F(3); alert(window.n)//fsfsf alert(2); var dd = new d(); alert(window.name)//空 alert(3); alert(dd.k);//4 alert(dd.h.name);//namename alert(dd.a.n);//fsfsf alert(window.k);//undefined alert(window.h.name);//Cannot read property ‘name‘ of undefined alert(window.a.n);//Cannot read property ‘n‘ of undefined function F(a){ this.n = 1; this.sc = 4; return new init(this);//this是F对象 } function init(a){ alert("111" + a.sc);//4 this.n = a.sc; return { k : this.n } } alert(1); var d = F(3); alert(d.k); //4 function F(a){ this.n = 1; this.sc = "scscsc"; } var d = new F(); alert(window.sc);//undefined </script> </head> <body> </body> </html>
原文：http://www.cnblogs.com/yaowen/p/6900332.html