How to Detect Arrow Key Presses in JavaScript: Why onkeypress Doesn't Work and the onkeydown Solution

Detecting Arrow Key Presses in JavaScript: A Comprehensive Guide

Detecting key presses is a common task in web development, especially when creating interactive controls. While most keys can be accurately detected using the onkeypress event listener, arrow keys pose a unique challenge. This article explores why arrow keys cannot be detected using onkeypress and provides a simple solution to capture arrow key presses in JavaScript.

The Arrow Key Dilemma

When using onkeypress to detect key presses, it works flawlessly for most keys. However, arrow keys (left, up, right, down) do not trigger the onkeypress event. This is because browsers handle arrow keys differently, initiating scrolling behavior by default.

Solution: Using onkeydown

To detect arrow key presses, you must use the onkeydown event listener instead of onkeypress. The onkeydown event fires whenever a key is pressed down, including arrow keys. Here's an updated version of your code snippet using onkeydown:

function checkKey(e) {
    var event = window.event ? window.event : e;
    console.log(event.keyCode);
}

Arrow Key Keycodes

To identify specific arrow keys, you can use their corresponding keycodes:

• Left: 37
• Up: 38
• Right: 39
• Down: 40

By comparing the event.keyCode to these values, you can easily determine which arrow key was pressed.

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