Window.setInterval( ) method used to execute specified code periodically.
This method was introduced in JavaScript 1.2. It is related to setTimeout.
setInterval() Method Syntax
We can use either of the following syntaxes.
The first syntax:
window.setInterval(code, interval);
Where code is a string of JS code that you want to execute periodically. Make sure to add semicolons to separate multiple statements.
interval is an integer value in milliseconds.
The second syntax:
window.setInterval(function, interval, args...);
Where function(required) is nothing but JS code as a function. IE 4 and earlier versions don’t support this parameter.
In args parameters(optional) we can pass any number of parameters. Not supported in IE 9 and earlier versions.
What does it return?
Well the periodic execution has to stop. So, it returns a value that we can pass to Window.clearInterval( ) which then can be used to cancel the periodic execution of the supplied code or function.
setInterval() method Examples
This example prints yogeshchauhan.com every 3 seconds:
Let’s modify the example above to print the time as well. It will add the time to the string yogeshchauhan.com every 3 seconds.
How to stop setInterval() execution?
As we saw earlier, we can use clearInterval() to stop the execution.
Let’s use the same example to stop the execution.
We must use a variable when creating the interval method to stop the execution using the clearInterval() method.
Let’s create a variable in the same example above and add a stop button to stop the execution.
I used setInterval() and clearInterval() to create a progress bar in this post.
How to pass parameters in setInterval()?
Let’s pass few parameters in the example above.
basics examples JS Methods method setInterval
