How to perform an action every couple of seconds?

Question

Can someone quickly and simply explain to me how to perform an action every couple of seconds using

var timeOut = setTimeout(FunctionName, 5000);

I want to run a function every 5 seconds.

http://jsfiddle.net/9WkRw/ this will update every second. This is on domready with jquery. — Matt, Aug 02 '11 at 09:17

score 34 · Accepted Answer · answered Aug 02 '11 at 09:13

34

As you asked for a method using setTimeout:

function doStuff() {
   console.log("hello!");
   setTimeout(doStuff, 5000);
}
setTimeout(doStuff, 5000);

But it would probably be better to use setInterval:

function doStuff() {
   console.log("hello!");
}
setInterval(doStuff, 5000);

answered Aug 02 '11 at 09:13

James Allardice

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What console.log does exactly? – Iladarsda Aug 02 '11 at 09:15
It prints whatever you tell it to print to the console (press F12 in newer browsers to open the console). – James Allardice Aug 02 '11 at 09:16
+1 for the example using `setTimeout` -- this is often the better way of meeting this need. – lonesomeday Aug 02 '11 at 09:16
1

What is the different between setTimeout and setInterval and in what cases are you better off to use either of those? – Iladarsda Aug 02 '11 at 09:18
@Pete - There is a great explanation of that here: http://stackoverflow.com/questions/729921/settimeout-or-setinterval – James Allardice Aug 02 '11 at 09:25

score 2 · Answer 2 · answered Aug 02 '11 at 09:13

2

Just put setTimeout at the end inside your function, with a call to itself - like a delayed tail-recursion.

answered Aug 02 '11 at 09:13

miku

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score 1 · Answer 3 · answered Aug 02 '11 at 09:12

1

Use setInterval:

var timeOut = setInterval(nextNotice, 5000);

answered Aug 02 '11 at 09:12

Igor Dymov

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score 1 · Answer 4 · answered Aug 02 '11 at 09:13

1

var myFunction = function() { 
     //Do stuff
     AnotherFunction();
};

var timeOut = setInterval(myFunction, 2000);

answered Aug 02 '11 at 09:13

Rob Stevenson-Leggett

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vaidas · Answer 5 · 2011-08-02T09:40:28.280

1

In the example below, when a button is clicked, the input field will start to count (for ever), starting at 0.

<html>
  <head>
    <script type="text/javascript">
      var c = 0;
      var t;
      var timer_is_on = false;

      function timedCount() {
        document.getElementById('txt').value = c;
        c = c + 1;
        t = setTimeout(timedCount, 1000);
      }

      function doTimer() {
        if (!timer_is_on) {
          timer_is_on = true;
          timedCount();
        }
      }
    </script>
  </head>
  <body>
    <form>
      <input type="button" value="Start count!" onclick="doTimer()">
      <input type="text" id="txt" />
    </form>
  </body>
</html>

edited Aug 02 '11 at 09:40

answered Aug 02 '11 at 09:13

vaidas

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9

[W3Schools is not a great resource](http://w3fools.com/). If you are linking an article on another site, please also summarise it here. – lonesomeday Aug 02 '11 at 09:17
But the resource has a perfect example: – vaidas Aug 02 '11 at 09:19
No, it has a functional example. There are numerous problems with that bit of code that make it a poor example (use of a number as a boolean, use of a string with `setTimeout`, no actual invocation of the code, meaningless variable names). – lonesomeday Aug 02 '11 at 09:27

Mark Redman · Answer 6 · 2011-08-02T09:30:04.303

1

you can do something like:

$(document).ready(function () 
        {
setTimeout(nextNotice, 5000);
}
function nextNotice()
{
// do stuff 
setTimeout(nextNotice, 5000);
}

edited Aug 02 '11 at 09:30

answered Aug 02 '11 at 09:14

Mark Redman

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Why setTimeout is used twice? – Iladarsda Aug 02 '11 at 09:16
true, you can just call nextNotice() in document ready function if you want the messages/actions to appear/process straight away, rather than waiting the set time. – Mark Redman Aug 02 '11 at 09:29

How to perform an action every couple of seconds?

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