//創(chuàng)建構(gòu)造函數(shù)         function Word(words){            this.words = words;         }         Word.prototype = {             alert(){                 alert(this.words);             }         }        //創(chuàng)建實(shí)例         var w = new Word("hello world");         w.print = function(){            console.log(this.words);            console.log(this);  //Person對(duì)象         }         w.print();  //hello world         w.alert();  //hello world{        alert(){             alert(this.words);         }     }     這個(gè)對(duì)象怎么理解？這是什么寫法？