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Js

一些特别的Js特性

2015-03-27Js0
1. (function () { return typeof arguments; })(); A. \"object\" B. \"array\" C. \"arguments\" D. \"undefined\" 答案:A 2. var f = function g() { return 23; }; type

1.


(function () {  
    return typeof arguments;  
})();  
A. "object"
B. "array"
C. "arguments"
D. "undefined"


答案:A

2.


var f = function g() {
        return 23;
    };
typeof g();
A. "number"
B. "undefined"
C. "function"
D. Eorror


答案:D

3.


(function (x) {
    delete x;
    return x;
})(1);
A. 1
B. null
C. undefined
D. Error


答案:A

4.


var y = 1,
    x = y = typeof x;
x;
A. 1
B. "number"
C. undefined
D. "undefined" 


答案: D

5.


(function f(f) {
    return typeof f();
})(function () {
    return 1;
});
A. "number"
B. "undefined"
C. "function"
D. Error


答案:A

6.


var foo = {
    bar: function () {
        return this.baz;
    },
    baz: 1
};
(function () {
    return typeof arguments[0]();
})(foo.bar);
A. "undefined"
B. "object"
C. "number"
D. "function"


答案:A

7.


var foo = {
    bar: function () {
        return this.baz;
    },
    baz: 1
};
typeof (f = foo.bar)();
A. "undefined"
B. "object"
C. "number"
D. "function"


答案:A

8.


var f = (function f() {
    return "1";
}, function g() {
    return 2;
})();
typeof f;
A. "string"
B. "number"
C. "function"
D. "undefined"


答案: B

9.


var x = 1;
if (function f() {}) {
    x += typeof f;
}
x;
A. 1
B. "1function"
C. "1undefined"
D. NaN


答案: C

10.


var x = [typeof x, typeof y][1];
typeof typeof x;
A. "number"
B. "string"
C. "undefined"
D. "object"


答案: B

11.


(function (foo) {
    return typeof foo.bar;
})({
    foo: {
        bar: 1
    }
});
A、“undefined” 
B、“object” 
C、“number” 
D、Error


答案: A

12.


(function f() {
    function f() {
        return 1;
    }
    return f();
    function f() {
        return 2;
    }
})();
A、1 
B、2 
C、Error (e.g. “Too much recursion”) 
D、undefined


答案:B

13.

function f() {
    return f;
}
new f() instanceof f;
A、true 
B、false


答案:B


14.


with (function(x, undefined){}) length;
A、1 
B、2 
C、undefined 
D、Error



答案:B

具体答案大家可以自己运行得出,为什么会得出这样的结果,我也有一些不懂的地方,怕误人子弟,所以这里就不解答这里的问题了。


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