How to Detect Key Press in Javascript

In this tutorial, you will learn how to detect key press in javascript. Keyboard events are triggered whenever a user interacts on a webpage using a keyboard such as typing some random text in an input field or pressing Enter key to submit a form.

There are 3 keyboard events keyup, keypress, and keydown. In the case of keyboard events, the event object contains certain properties and that can help us in detecting which key is pressed by the user. In our case, we are going to use the key property.

In the following example, we have one input field in which we will enter some random text.  As we start typing, we will display the letters one by one on the screen.  Please have a look over the code example and steps given below.

HTML & CSS

  • We have 3 elements in the HTML file (div, input, and h1). The div element is just a wrapper for the rest of the elements.
  • The inner text for the h1 element is “Result”, which will be later replaced by letters using javascript.
  • We have done some basic styling using CSS and added the link to our style.css stylesheet inside the head element.
  • We have also included our javascript file script.js with a script tag at the bottom.
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <link rel="stylesheet" href="style.css">
    <title>Document</title>
</head>
<body>
    
    <div class="container">
        <input type="text">
        <h1>Result</h1>
    </div>

    <script src="script.js"></script>
</body>
</html>
.container {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

Javascript

  • We have selected the h1 element using the document.querySelector() method and stored it in the result variable.
  • We have attached the keyup event listener to the window.
  • In the event handler function, we are using the key property of the event object to get the key pressed by the user and setting it as innerText of the h1 element.
let result = document.querySelector('h1');

window.addEventListener('keyup', (e) => {
    result.innerText = e.key;
});
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