[javascript] Put a Delay in Javascript

I need to add a delay of about 100 miliseconds to my Javascript code but I don't want to use the setTimeout function of the window object and I don't want to use a busy loop. Does anyone have any suggestions?

This question is related to javascript

The answer is


If you're okay with ES2017, await is good:

const DEF_DELAY = 1000;

function sleep(ms) {
  return new Promise(resolve => setTimeout(resolve, ms || DEF_DELAY));
}

await sleep(100);

Note that the await part needs to be in an async function:

//IIAFE (immediately invoked async function expression)
(async()=>{
  //Do some stuff
  await sleep(100);
  //Do some more stuff
})()

Use a AJAX function which will call a php page synchronously and then in that page you can put the php usleep() function which will act as a delay.

function delay(t){

var xmlhttp;

if (window.XMLHttpRequest)

{// code for IE7+, Firefox, Chrome, Opera, Safari

xmlhttp=new XMLHttpRequest();

}

else

{// code for IE6, IE5

xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");

}

xmlhttp.open("POST","http://www.hklabs.org/files/delay.php?time="+t,false);

//This will call the page named delay.php and the response will be sent to a division with ID as "response"

xmlhttp.send();

document.getElementById("response").innerHTML=xmlhttp.responseText;

}

http://www.hklabs.org/articles/put-delay-in-javascript


Actually only setTimeout is fine for that job and normally you cannot set exact delays with non determined methods as busy loops.


This thread has a good discussion and a useful solution:

function pause( iMilliseconds )
{
    var sDialogScript = 'window.setTimeout( function () { window.close(); }, ' + iMilliseconds + ');';
    window.showModalDialog('javascript:document.writeln ("<script>' + sDialogScript + '<' + '/script>")');
}

Unfortunately it appears that this doesn't work in some versions of IE, but the thread has many other worthy proposals if that proves to be a problem for you.


I just had an issue where I needed to solve this properly.

Via Ajax, a script gets X (0-10) messages. What I wanted to do: Add one message to the DOM every 10 Seconds.

the code I ended up with:

$.each(messages, function(idx, el){
  window.setTimeout(function(){
    doSomething(el);
  },Math.floor(idx+1)*10000);
});

Basically, think of the timeouts as a "timeline" of your script.

This is what we WANT to code:

DoSomething();
WaitAndDoNothing(5000);
DoSomethingOther();
WaitAndDoNothing(5000);
DoEvenMore();

This is HOW WE NEED TO TELL IT TO THE JAVASCRIPT:

At Runtime 0    : DoSomething();
At Runtime 5000 : DoSomethingOther();
At Runtime 10000: DoEvenMore();

Hope this helps.