前端测试(2)

}(); ＜/script＞

D.＜script language=\＞ function(){ alert('Hello JS！') }(); ＜/script＞

11. 以下关于Javascript原生对象的用法错误： A.var boo = new Boolean(true) B.varstr = new String('Hello') C.var number = new Number(1337) D.var math = new Math(198);

12. 以下关于实例化对象的语法正确的是： A.var a = new A();

B.var a = new A; C.var a = A(); D.var a = A;

13. 以下是构造函数的方式自定义对象的代码，请选择语法正确的选项：

A.＜script language=\＞ function User(name, sex, age) { this.name = name; this.sex = sex; this.sleep = function() { alert(this.name + '睡觉啦'); } }

＜/script＞

B.＜script language=\＞ function User(name, sex, age) { User.name = name; User.sex = sex; User.sleep = function() { alert(this.name + '睡觉啦'); } }

＜/script＞

C.＜script language=\＞

var User(name, sex, age) { this.name = name; this.sex = sex; this.sleep = function() { alert(this.name + '睡觉啦'); } }

＜/script＞

D.＜script language=\＞ var User(name, sex, age) { User.name = name; User.sex = sex; User.sleep = function() { alert(this.name + '睡觉啦'); } }

＜/script＞

14. ＜script＞

var a=”hello, JavaScript”; alert(typeof a);

＜/script＞ 输出结果为 A.hello,JavaScript B.string C.a D.object

15. 以下是构造函数及原型混合方式自定义对象的代码，请选择语法正确的选项：

A.＜script language=\＞ function User(name, sex, age) { this.name = name; this.sex = sex; }

User.prototype.sleep = function() { alert(this.name + '睡觉啦'); }

＜/script＞

B.＜script language=\＞ function User(name, sex, age) { this.name = name;

this.sex = sex; }

User.this.sleep = function() { alert(this.name + '睡觉啦'); }

＜/script＞

C.＜script language=\＞ function User(name, sex, age) { User.name = name; User.sex = sex; }

User.prototype.sleep = function() { alert(this.name + '睡觉啦'); }

＜/script＞

D.＜script language=\＞ function User(name, sex, age) { User.name = name; User.sex = sex; }

User.sleep = function() { alert(this.name + '睡觉啦');