Since 2009 when this question was asked, JavaScript has evolved significantly. All other answers are now obsolete or overly complicated. Here is the current best practice:
function sleep(ms) {
return new Promise(resolve => setTimeout(resolve, ms));
}
async function demo() {
console.log('Taking a break...');
await sleep(2000);
console.log('Two seconds later, showing sleep in a loop...');
// Sleep in loop
for (let i = 0; i < 5; i++) {
if (i === 3)
await sleep(2000);
console.log(i);
}
}
demo();
This is it. await sleep(<duration>)
.
Note that,
await
can only be executed in functions prefixed with the async
keyword, or at the top level of your script in some environments (e.g. the Chrome DevTools console, or Runkit).
await
only pauses the current async
function
Two new JavaScript features helped write this "sleep" function:
Compatibility
If for some weird reason you're using Node older than 7 (which has reached end of life), or are targeting old browsers, async
/await
can still be used via Babel (a tool that will transpile JavaScript + new features into plain old JavaScript), with the transform-async-to-generator
plugin.
The simple answer is that there is no such function.
The closest thing you have is:
var millisecondsToWait = 500;
setTimeout(function() {
// Whatever you want to do after the wait
}, millisecondsToWait);
Note that you especially don't want to busy-wait (e.g. in a spin loop), since your browser is almost certainly executing your JavaScript in a single-threaded environment.
Here are a couple of other SO questions that deal with threads in JavaScript:
And this question may also be helpful:
Built in javascript setTimeout.
setTimeout(
function()
{
//do something special
}, 5000);
UPDATE: you want to wait since when the page has finished loading, so put that code inside your $(document).ready(...);
script.
UPDATE 2: jquery 1.4.0 introduced the .delay
method. Check it out. Note that .delay only works with the jQuery effects queues.