Recursive setInterval() runs continuously

问题:

I'm trying to run a function every 5 seconds using JavaScript using a recursive setInterval function.

The following code just logs "started" as fast as possible and then crashes the browser. Why is this not running every 5 seconds?

function five() {
console.log("five");
setInterval(five(), 5000);
}
five();

回答1:

Don't use setInterval this way. Use setTimeout. By calling setInterval, you create a UNIQUE timer every time the function is called. SetTimeout would create one timer that ends, and then creates a new timer.

You should also change the way you reference five. five() executes the function immediately. Just five passes a function reference, so do it as you see below.

function five() {
    console.log("five");
    setTimeout(five, 5000);
}
five();

Of course, you can always pass the function call as a string to be evaluated:

    setTimeout("five()", 5000); // note the quotes

But this is generally considered bad practice.

回答2:

You're calling five immediately, instead of merely passing it in:

function five () {
    console.log("five");
}
setInterval(five, 5000);
/*              ^     */

回答3:

Change this line:

setInterval(five(), 5000);

like this:

setInterval(five, 5000);

But seems like what you really need is:

setTimeout(five, 5000);

So your code will look like:

function five() {
   console.log("five");
   setTimeout(five, 5000);
}
five();

回答4:

The reason of crashing it is that you are calling the function five. Instead of that you should pass it as parameter.

setInterval(five, 5000);