js题集8

Posted 2020-10-01 tong24

1.

var f = true;

if (f === true) {

  var a = 10;

}

 

function fn() {

  var b = 20;

  c = 30;

}

 

fn();

console.log(a);

console.log(b);

console.log(c);

2.

var x = 1;

var y = 0;

var z = 0;

function add(n){n=n+1;}

y = add(x);

function add(n){n=n+3;}

z = add(x);

3.

for(i=0, j=0; i<10, j<6; i++, j++){

  k = i + j;

}

4.

var two = 0.2;

var one = 0.1;

var eight = 0.8;

var six = 0.6;

[two -one == one,eight- six == two];

运行结果，求更严谨的写法。

5.

编写一个方法 去掉一个数组的重复元素

eg：var arr = [1,2,3,1,43,12,12,1];

6.

javascript中如何检测一个变量是一个String类型？

7.

实现

“hello world”  -> ‘h e l l o  w o r l d’