javascript - 为什么 setinterval 带回一个整数(新手)

Question

function myTimer() {
   return new Date().toLocaleTimeString();
}

setInterval(function(){ myTimer() }, 1000);

为什么单独调用 myTimer 会按预期返回字符串，但通过 setInterval 调用时会返回整数？

Answer 1

The returned timeoutID is a numeric, non-zero value which identifies the timer created by the call to setInterval(); this value can be passed to Window.clearInterval() to cancel the timeout.

详细信息: https://developer.mozilla.org/en-US/docs/Web/API/WindowTimers/setInterval