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I have a javascript file, and in several places I want to add a small delay, so the script would reach that point, wait 3 seconds, and then continue with the rest of the code. The best way that I thought of doing this was to create a function, which I could call from anywhere in the script.

function startDelay(lengthOfDelay)
{
//code to make it delay for lengthOfDelay amount of time
}

However, I can not find any way to implement the code to make it wait. I had a look at setTimeout, but you needed to hard code the function into it, which made it no good for me.

Is there any way that I can get the script to juct pause for a few seconds? I have no problem with the UI freezing whilst the code is paused.

If not, is there a way that I could use the PHP sleep() to achieve this? (I know that PHP is server side and Javascript is client side, but maybe there is a way that I have not heard of.)

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3
  • 2
    The simplest way is to use setTimeout and to do the remaining of your code in the function you give to setTimeout. Commented Jun 1, 2013 at 14:49
  • 1
    stackoverflow.com/questions/10312963/javascript-settimeout Commented Jun 1, 2013 at 14:50
  • just create a promise that return a settimeout, and use it in a async function to use the await: const delay =async(seconds)=>new Promise( resolve=>setTimeout(resolve,seconds)); /////// Commented Jun 10, 2023 at 19:43

3 Answers 3

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70

You do not need to use an anonymous function with setTimeout. You can do something like this:

setTimeout(doSomething, 3000);

function doSomething() {
   //do whatever you want here
}
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4 Comments

How would I create a function such as startDelay(lengthOfDelay) that I could call from anywhere in the script and have it do the rest of the code afterwards, not just //do whatever you want here?
I'm not really sure what you want to do exactly. Do you want to halt the execution of the page or schedule a function that will execute after a delay?
@Kassem I think (s)he means e.g. what if you want to console.log a message every second using a for loop? i.e. while(true){ [a delay function, incorporating console.log]} I don't think your function will run sequentially.
Didn't work for me the first time, but the following solved my problem: setTimeout(function() { doSomething(); }, 3000);
5

Ah yes. Welcome to Asynchronous execution.

Basically, pausing a script would cause the browser and page to become unresponsive for 3 seconds. This is horrible for web apps, and so isn't supported.

Instead, you have to think "event-based". Use setTimeout to call a function after a certain amount of time, which will continue to run the JavaScript on the page during that time.

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2 Comments

Is there any way to do this? Making the page unresponsive is actually a positive thing for me!
fortunatelly yes: sleep.js stackoverflow.com/a/16873849/667927
-3

You can create a delay using the following example

setInterval(function(){alert("Hello")},3000);

Replace 3000 with # of milliseconds

You can place the content of what you want executed inside the function.

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5 Comments

This answer is slightly lacking (I think) because setInterval will continue to run every 3 seconds, not just once.
@AdamDavis I've tested this method and I haven't experienced any problems. Should you or someone else test this and demonstrate otherwise let the community know. Thanks
@CBC_NS I just tried it out and I also had it repeating every 3 seconds. Handy to keep in mind though.
This answer is wrong. The original post states, "I want to add a small delay, so the script would reach that point, wait 3 seconds, and then continue with the rest of the code." This code will continually call the declared function every n milliseconds until a clearInterval is set. This could have very bad unintended consequences.
just replace setInterval with setTimeout and it works as intended

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