[译]Javascript quiz

原文:http://asenbozhilov.com/articles/quiz.html

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这些题目都源自ECMA-262-3规范.Good luck!

译者注:作者是根据ES3出的题,但我没发现和ES5有不同表现的地方.暂时不给出答案解释.请到http://ecma-international.org/ecma-262/5.1/找答案

 

1. Function.prototype.toString.call({
       name: 'F', 
       body: 'print("Javascript is hard")'
   });

   2. TypeError
   3. empty string
   4. [object Function]

2. new String({
       toString : function (){ return this;}, 
       valueOf : function () {return this;}
   });

   1. TypeError
   2. String value
   3. String object
   4. Object

3. typeof (new Date() + new Date());

   1. number
   2. object
   3. string
   4. undefined

4. typeof (void null);

   1. object
   2. null
   3. undefined
   4. SyntaxError

5. function F() {}
   F.prototype = new Function;
   Object.prototype.toString.call(new F());

   1. [object Function]
   2. [object Array]
   3. [object String]
   4. [object Object]

6. [].length = -2;

   1. TypeError
   2. -2
   3. RangeError
   4. 0

7. var D = Math.pow(2, 33);
   (D | D) == D;

   1. true
   2. false
   3. RangeError

8. '_string_'.replace(/^/, "$'");

   1. _string_
   2. '_string_
   3. $'_string_
   4. _string__string_

9. eval('typeof F; function F() {}'); 

   1. undefined
   2. object
   3. string
   4. function

10. debugger; 

    1. 给微软寄钱
    2. 可能会SyntaxError
    3. 把你的源代码通过电子邮件发送给Brendan Eich
    4. ReferenceError
    5. 在Windows启动时扫描病毒

 

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