06.代码输出结果

2021-04-08

1.

function fn2(){
  for(var i=0;i<4;i++){
    var timer=setInterval(function(i,timer){
      console.log(i);
      clearInterval(timer)
    },10,i,timer);
  }
}
fn2();

输出：0 1 2 3 3 3 3 重复

2.

function fn1(){
  for(var i=0;i<4;i++){
    var timer=setTimeout(function(i){
      console.log(i);
      clearTimeout(timer)
    },10,i);
  }
}
fn1();

输出：0 1 2

3.

const a = [];
for (var i = 0; i < 10; i++) {
  a.push(function () {
    return console.log(i);
  });
}
a[0]();
a[1]();

输出：10 10

4.

var m = true;
setTimeout(function() {
    m = false;
},3000);
while(m) { }
console.log('DONE');

输出：无输出

var m = true;
setTimeout(
  function() {
    m = false;
  }, 3000);
);
while(m) {}
console.log('DONE');

输出：报错Uncaught SyntaxError: Unexpected token ‘)’

5.

console.log(0.25 + 0.25 === 0.5);
console.log(0.1 + 0.2 === 0.3);

输出：true false