Go语言视频零基础入门到精通

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1. Object.prototype.extend = function (Parent) {   
2.     this.prototype = new Parent();   
3. }   
4. Rectangle = function (width, height) {   
5.     this.width = width;   
6.     this.height = height;   
7. }   
8. Rectangle.prototype.area = function () {   
9.     return this.width * this.height;   
10. }   
11. Square = function (width) {   
12.     this.__proto__.width = width;   
13.     this.__proto__.height = width;   
14.     this.whoami = function () {   
15.         return "I am a Square.";   
16.     }   
17. }   
18. Square.extend(Rectangle);   
19.    
20. var s = new Square(5);   
21. document.writeln(s.area());  // The output is 25.   
22. document.writeln(s.whoami()); // The output is "I am a Square."   
24. Object.prototype.extend = function (Parent) {
25.     this.prototype = new Parent();
26. }
27. Rectangle = function (width, height) {
28.     this.width = width;
29.     this.height = height;
30. }
31. Rectangle.prototype.area = function () {
32.     return this.width * this.height;
33. }
34. Square = function (width) {
35.     this.__proto__.width = width;
36.     this.__proto__.height = width;
37.     this.whoami = function () {
38.         return "I am a Square.";
39.     }
40. }
41. Square.extend(Rectangle);
43. var s = new Square(5);
44. document.writeln(s.area());  // The output is 25.
45. document.writeln(s.whoami()); // The output is "I am a Square."

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以上代码存在很多问题，不知你能说出几个？