timer - Javascript - setTimeout undefined? - Stack Overflow

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For a reason that I cannot fathom, the following function doesn't seem to work.

function timerTick()
{
    var t=setTimeout(timerTick,1000);
}

Everything should be working, but when I call the function, the console simply says 'undefined'.

Ideas?

For a reason that I cannot fathom, the following function doesn't seem to work.

function timerTick()
{
    var t=setTimeout(timerTick,1000);
}

Everything should be working, but when I call the function, the console simply says 'undefined'.

Ideas?

• javascript
• timer
• undefined
• settimeout

Share Improve this question Follow asked Aug 19, 2011 at 11:55 help mehelp me 911 silver badge22 bronze badges 6

• 1 Why are you assigning the value to a var that never gets referenced again? Do you mean to return the result of setTimeout instead? – Andrzej Doyle Commented Aug 19, 2011 at 11:57
• The console output must e from somewhere else, the function is perfectly valid. – David Hellsing Commented Aug 19, 2011 at 11:58
• Add alert('i am called'); inside timerTick(). If you are calling it from the console then 'undefined' is correct behaviour, since the function call produces no return object. – arunkumar Commented Aug 19, 2011 at 11:59
• setTimeout returns a timeout ID, which can be used to clear the timeout. Are you trying to find out how many milliseconds the setTimeout has left? – Alex Commented Aug 19, 2011 at 12:00
• I'm trying to make an recursively looping function. I added the alert - it pops up once, then the console says 'undefined' and it never shows again. – help me Commented Aug 19, 2011 at 12:01

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2 Answers 2

Sorted by: Reset to default 5

Everything IS working. What you're seeing is the return value of the invokation of timerTick itself which, as it stands, does not have a return statement and whose return value will thus be undefined. (The local variable t is not returned automatically!)

If you add a

console.log( "It's me. Again!" );

inside timerTick and call it you'll be seeing it every second in the console as expected.

EDIT: Typo in code and clarification: The return value of functions not invoked from the console, such as through setTimeout or setInterval, will not be printed to the console.

Everything should be working, but when I call the function, the console simply says 'undefined'.

Ideas?

May be your past this code into console and press enter (for example, in Chrome)? In this case console says 'undefined'. If your need to run function timerTick try next: 1)

function timerTick()
{
    console.info('i am called');
    var t=setTimeout(timerTick,1000);
}
timerTick();

or 2)

(function timerTick()
{
    console.info('i am called');
    var t=setTimeout(timerTick,1000);
})();

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