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Table of contents
Understanding onkeyup
Working with onkeyup
Event Object
Frequently Asked Questions
What does onkeyup do in JavaScript?
How is onkeyup different from onkeydown and onkeypress?
Can I use onkeyup to get the key pressed by the user?
Last Updated: Mar 27, 2024

JavaScript onkeyup

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Anubhav Sinha
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25 Jun, 2024 @ 01:30 PM


In web development, making your site interactive is key to creating a great user experience. To do this, you need to respond to user actions, such as clicks, mouse movements, or keystrokes. JavaScript provides a host of event handlers to help with this, and one such handler is onkeyup. This article will delve into what onkeyup is, how it works, and when you should use it.

JavaScript onkeyup

Understanding onkeyup

The onkeyup event in Javascript is triggered when a user releases a key on the keyboard. This is different from onkeydown, which is triggered when a key is pressed down, and onkeypress, which is activated when a key is pressed down and then released.


Here's a simple example of using onkeyup:

document.getElementById("inputField").onkeyup = function() { 
    console.log('Key has been released!'); 


In this code, a message is logged to the console whenever a key is released in the input field with the ID inputField.

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Working with onkeyup

Now, let's explore a practical use of onkeyup. Imagine you want to create a dynamic search input that shows results as you type. To avoid making a request on every keystroke, you could use a combination of setTimeout and clearTimeout (as mentioned in the previous section), and implement this within an onkeyup event.

let timerId;
document.getElementById('search-box').onkeyup = function(e) {
    timerId = setTimeout(() => {
        // send request and show results
    }, 1000);


In this snippet, the onkeyup event clears the timeout, preventing the request from being sent prematurely, and then sets a new timeout. If another key is pressed within the one-second interval, the timer resets.

Event Object

When an event is triggered, JavaScript automatically creates an event object that contains details about the event. You can use this event object in the onkeyup event to retrieve the character of the released key.

document.getElementById("inputField").onkeyup = function(event) { 
    console.log('Key released: ' + event.key); 


In this example, event.key is used to log the released key.

Frequently Asked Questions

What does onkeyup do in JavaScript?

onkeyup is an event that triggers a function when a user releases a key on the keyboard.

How is onkeyup different from onkeydown and onkeypress?

onkeyup triggers when a key is released, onkeydown triggers when a key is pressed down, and onkeypress triggers when a key is pressed and released.

Can I use onkeyup to get the key pressed by the user?

Yes, you can use the event.key property in the onkeyup event function to get the key released by the user.


In JavaScript, onkeyup is a vital tool in your interactive web development toolbox. It enables you to capture and respond to key release events, allowing for a more interactive and responsive user experience. From dynamic search boxes to game controls, there's a multitude of applications for this handy event. By understanding and correctly utilizing onkeyup, you can significantly enhance your website or application's interactivity and overall user experience.

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