# HTML onkeydown Event Attribute
The `onkeydown` event attribute triggers a script when a user presses a key on the keyboard. It is a fundamental keyboard event used to capture user input, build interactive shortcuts, and control web applications.
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## Introduction
The `onkeydown` attribute is part of the HTML Event Attributes set. It fires the moment a key on the keyboard is pressed down, even before the character is rendered on the screen.
### The Keyboard Event Sequence
When a user presses and releases a key, a sequence of three events occurs in order:
1. **`onkeydown`** (The key is pressed down)
2. **`onkeypress`** (The key is pressed and produces a character value - *Deprecated in modern web standards*)
3. **`onkeyup`** (The key is released)
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## Browser Support
| Chrome | Edge | Firefox | Safari | Opera |
| :---: | :---: | :---: | :---: | :---: |
| Yes | Yes | Yes | Yes | Yes |
The `onkeydown` attribute is fully supported by all major modern web browsers.
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## Syntax
You can define the `onkeydown` attribute inline within an HTML element:
```html
```
### Attribute Values
| Value | Description |
| :--- | :--- |
| *script* | The JavaScript code or function to be executed when the `onkeydown` event is triggered. |
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## Code Examples
### Example 1: Basic Inline Usage
This example triggers a JavaScript function when a user presses a key inside the text input field.
```html
onkeydown Demo
Press any key inside the input box below:
```
### Example 2: Detecting Which Key Was Pressed
In modern web development, it is common to pass the event object (`event`) to determine exactly which key was pressed using the `event.key` or `event.code` properties.
```html
Detect Key Press
Type something in the input field to see the key name:
```
---
## Considerations & Best Practices
### Unsupported Elements
The `onkeydown` attribute cannot be used with the following HTML elements:
* ``, ``, ` `, ``, ``, `
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