1. //1.
    2. var x=0,
    3.     y=1;
    4. function fn(y){
    5.     y+=2;
    6.     fn=function(x){
    7.         x+=3;
    8.         console.log(x+y);
    9.     };
    10.     console.log(x+y);
    11. }
    12. fn(4);
    13. fn(5);
    14. console.log(x+y);
    17. //2.
    18. var x = 2;
    19. var obj = {
    20.     x: 3,
    21.     fn: function (x) {
    22.         this.x += --x;
    23.         console.log(x);
    24.     }
    25. };
    26. var fn = obj.fn;
    27. obj.fn(4);
    28. fn(5);
    29. console.log(x, obj.x);
    31. //3.
    32. var x = 3,
    33.     obj = { x: 2 };
    34. obj.fn = (function () {
    35.     x++;
    36.     this.x += x;
    37.     return function (y) {
    38.         x++;
    39.         y += x;
    40.         this.x += y;
    41.         console.log(x);
    42.     }
    43. })();
    44. var fn = obj.fn;
    45. obj.fn(1);
    46. fn(4);
    47. console.log(x, obj.x)
    49. //4.
    50. //选项卡
    52. //5.
    53. let y = {
    54.     n: 10,
    55.     fn: (function (x) {
    56.         console.log(x);
    57.         return function () {
    58.             console.log(this.n + x);
    59.         }
    60.     })(y.n) //=>Uncaught ReferenceError: Cannot access 'y' before initialization
    61. };
    62. y.fn();
    64. //6.
    65. //this问题总结