Javascript setInterval(); does not work?

Question

I am trying to make a script that changes the header's color every second, I have made a function that styles a HTML element with a random color whenever it's called, and when I use the setInterval(); it does not work!

function randomColor(elementId) {
var colors = ["red","green","blue","purple","lightblue","cyan","yellow","brown","pink","grey"];
var randomNumber = Math.floor(Math.random() * 10) + 1;
document.getElementById(elementId).style.color = colors[randomNumber];
}

setInterval(randomColor("Header"), 1000);

Can someone help? thanks!

Note: When I refresh the page it only changes the color once.

See http://stackoverflow.com/q/457826/256305 – Mike Godin Jan 25 '17 at 18:30 — Mike Godin, Jan 25 '17 at 18:30

score 3 · Accepted Answer · edited Jul 02 '23 at 21:07

3

It's because you are calling randomColor and the result to that function is being passed into setInterval.

You should be able to pass a wrapped version in just fine:

setInterval(function() { randomColor("Header"); }, 1000);

edited Jul 02 '23 at 21:07

halfer

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answered Jan 25 '17 at 18:26

Daniel A. White

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score 2 · Answer 2 · answered Jan 25 '17 at 18:26

2

The setInterval function takes as input a function. In your example, you are executing randomColor("Header") and sending the result to the setTimer function.

setInterval(function() { randomColor("Header") }, 1000);

answered Jan 25 '17 at 18:26

dana

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score 1 · Answer 3 · edited Jan 25 '17 at 18:29

1

You should send a function as arugment in setInterval, like this:

setInterval(function(){randomColor("Header")}, 1000);

edited Jan 25 '17 at 18:29

Antony

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answered Jan 25 '17 at 18:26

Man Programmer

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Javascript setInterval(); does not work?

3 Answers3