Why does setTimeout() "break" for large millisecond delay values?

javascript settimeout
Matt Ball picture Matt Ball · Aug 12, 2010 · Viewed 38.4k times · Source

I came across some unexpected behavior when passing a large millisecond value to setTimeout(). For instance,

setTimeout(some_callback, Number.MAX_VALUE);

and

setTimeout(some_callback, Infinity);

both cause some_callback to be run almost immediately, as if I'd passed 0 instead of a large number as the delay.

Why does this happen?

Answer

OneSHOT picture OneSHOT · Aug 12, 2010

This is due to setTimeout using a 32 bit int to store the delay so the max value allowed would be 

2147483647

if you try 

2147483648

you get your problem occurring.

I can only presume this is causing some form of internal exception in the JS Engine and causing the function to fire immediately rather than not at all.

Related questions

How can I pass a parameter to a setTimeout() callback?

I have some JavaScript code that looks like: function statechangedPostQuestion() { //alert("statechangedPostQuestion"); if (xmlhttp.readyState==4) { var topicId = xmlhttp.responseText; setTimeout("postinsql(topicId)",4000); } } function postinsql(topicId) { //alert(topicId); } I get an error that topicId is not defined Everything was working before …

Read More
Execute script after specific delay using JavaScript

Is there any JavaScript method similar to the jQuery delay() or wait() (to delay the execution of a script for a specific amount of time)?

Read More
Difference between setTimeout with and without quotes and parentheses

I am learning JavaScript and I have learned recently about JavaScript timing events. When I learned about setTimeout at W3Schools, I noticed a strange figure which I didn’t run into before. They are using double quotes and then …

Read More