//創建構造函數         function Word(words){            this.words = words;         }         Word.prototype = {             alert(){                 alert(this.words);             }         }        //創建實例         var w = new Word("hello world");         w.print = function(){            console.log(this.words);            console.log(this);  //Person對象         }         w.print();  //hello world         w.alert();  //hello world{        alert(){             alert(this.words);         }     }     這個對象怎么理解？這是什么寫法？