function foo() {

             bar.apply(null, arguments);

         }

         function bar(){

             console.log(arguments);

         }

         foo(1,2,3,4,5);

结果：（1，2，3，4，5）

 function b(x, y, a){

             arguments[2] = 10;

             alert(a);

         }

         b(1, 2, 3);

结果：10

 var f = (

             function f(){

                 return "1";

             },

             function g(){

                 return 2;

             }

         )();

         typeof f;

结果；"number"
逗号运算符：（x，y），输入结果是：两个值进行比较，谁大输出谁

 var x = 1;

         if (function f(){}) {

             x += typeof f;

         }

 console.log(x);

结果："1undefined"

 var num = (function(n){

            if (n == 1){

                return 1;

            }

            return n * arguments.callee(n-1);

        }(100))

 var foo = '123';

         function print(){

             var foo = '456';

             this.foo = '789';

             console.log(foo);

         }

         print();

结果：456

  var foo = '123';

         function print(){

             this.foo = '789';

             console.log(foo);

         }

         print();

结果：789

  var foo = '123';

         function print(){

             this.foo = '789';

             console.log(foo);

         }

    new print();

结果：123

    var bar = {a: "002"};

         function print(){

             bar.a = 'a';

             Object.prototype.b = 'b';

             return function inner() {

                 console.log(bar.a);

                 console.log(bar.b);

             }

         }

         print()();

结果：a

     b

    var bar = {a: "002"};

         function print(){

             bar.a = 'a';

             Object.prototype.b = 'b';

             return function inner() {

                 console.log(bar.a);

                 console.log(bar.b);

             }

         }

         print()();

 var obj = {

             "2" : "a",

             "3" : "b",

             "length" : 2,

             "push" : Array.prototype.push

         }

         obj.push("c");

         obj.push("d");

 //obj为？

结果：{2: "c", 3: "d", length: 4}

解析：类属性

        属性要为索引，必须要有length，最好有push

        Array.prototype.push = function(target) {

             obj[obj.length] = target;

             obj.length++;

        }