第一题
var product = 'apple'
;
var obj =
{
produc:'pen'
,
prop:{
product:'apple pen'
,
getProduct:function(){
return this.product;
}
}
}
product='pineapple'
;
console.log(obj.prop.getProduct());
var buy =
obj.prop.getProduct;
console.log(buy());
======
执行结果为
=========================
apple pen
=========================
pineapple
第二题 考察箭头函数
window.name = 'A'
const obj =
{
name:'B'
,
getName:()=>
{
console.log(this.name);
console.log(this);
}
}
const fn =
obj.getName;
fn();
obj.getName();
fn.call({name:'c'
})
=====================
执行结果为 A A A
第三题 考察arguments对象里是实参值
function test(a,b){
console.log(arguments)
return arguments+b+arguments[2
];
}
var result = test('a','b','c','d'
);
console.log(result)
第四题
var a = { x:1
};
var b =
a;
a = a.x={x:1
};
console.log(a)
console.log(b)
// ====================执行结果为
// Object{x:1};
// Object{x:{x:1}}
第五题
var num = 1
;
function myFunc(){
alert(num); //undefined
var num =2
;
alert(num); // 2
}
myFunc();
第六题
var v1 = 'global'
;
var f1 =
function(){
console.log(v1);
};
f1(); //global
var f2 =
function(){
var v1 = 'local'
;
f1();
};
f2(); //global
第七题 ??
var name = "global"
;
var obj =
{
name:"local"
,
foo:function(){
this.name = 'foo'
;
}.bind(window)
};
var bar =
new obj.foo();
setTimeout(function(){
console.log(window.name) //global
},0
)
console.log(bar.name); //foo
var bar3=bar2=
bar;
bar2.name = 'foo2'
;
console.log(bar3.name); //foo2
第八题 题目有问题
var objName = " name1"
;
function obj(){
var objName = " name2"
;
funciton innerObj(){
alert(objName);
}
innerObj();
}
alert(obj());
第九题
window.a = 300
;
function fn1(){
this.a = 100
;
this.b = 200
;
return function(){
alert(this.a)
}.call(arguments[0
]);
}
function fn2(){
this.a =
new fn1();
}
var a =
new fn1().b;
var v =
new fn1(fn2());
分别弹出 300 200
[object Object]
第十题 ？？
function Dog(){}
Dog.prototype =
{
bark(){
console.log(1
)
}
}
const dog =
new Dog()
dog.bark()
Dog.prototype =
{
bark(){
console.log(2
)
}
}
dog.bark()
Dog.prototype =
{
bark(){
console.log(3
)
}
}
dog.bark()
输出三个 1
第十题
let num = 10
;
let output = ''
;
for(let i=1;i<=num;i++
){
let sqRoot =
Math.sqrt(i);
if(Math.floor(sqRoot)!==
sqRoot){
continue;
}
output+=i+''
;
}
console.log(output);
第十一题
const name ='name'
;
const test = `${name}`"${name}"
`${name}`;
console.log(test);
const name = 'name'
;
const test =
{name};
console.log(test)
第十二题
"use strict"
;
a = 1
;
var a = 2
;
console.log(window.a); //2
console.log(a);
//2
第十三题
var {a,b,c}={"c":10,"b":9,"a":8
}
console.log(a) //8
console.log(b)
//9
console.log(c)
//10
第十四题
console.log(NaN==
false)
//false
console.log(!NaN==
false)
//false
console.log(!!NaN==
false)
//true
console.log(NaN==
true)
//false
console.log(!NaN==
true)
//true
console.log(!!NaN==
true)
//false
// 第十五题
function test(a,b){
return a+b+arguments[2
];
}
var result = test("a","b","c","d"
)
console.log(result); //abc
第十六题
var a =
new Date(2020,3,8
)
console.log(a)
// Date Wed Apr 08 2020 00:00:00 GMT+0800 (中国标准时间)
