setTimeout定时器

let speed = 2000
function fun(){
    setTimeout(fun, speed+= 1000)
    console.log(1)
    console.log(speed)
}

setTimeout(fun, speed)

setInterval循环定时器

  var t = 2000;
    var set1 = setInterval(fn, t);
    function fn() {
        console.log('我是用来测试打印速度的');
        t += 100;
        console.log(t)
        clearInterval(set1);
        if (t > 0) {
            set1 = setInterval(fn, t);
        }
    }