Keyboard events

Full documentation on the MDN site

Keyboard events are

keydown	fired when any key on the keyboard is pressed down
keypress	a key is pressed down and that key normally produces a character value. For instance, when entering Ctrl+C, the event keypress is only fired when the key C is pressed down, whereas keydown is fired as soon as the Ctrl key is pressed
keyup	a key is released

`DOMEvent` object attributes

For keyboard events, the DOMEvent instance has the following attributes

altKey

True if the Alt (or Option, on Mac) key was active when the key event was generated

It is usually used with keypress, to be able to test if Alt+<key> was entered, or just <key>

Example

Enter text in the field below, with or without pressing the Alt key

Code

from browser import document

# the entry field has the id "altKey"
def keypress(ev):
    document["traceAltKey"].text = f"altKey: {ev.altKey}"

document["altKey"].bind("keypress", keypress)

key

A string for the key pressed:

- the character if the key produces a character

- a string that describes the key for special keys (eg "Control" for the Ctrl key)

Example

Put the cursor in the input boxes below and hit keys on the keyboard

keydown
keypress
keyup

Code

from browser import bind, document

def keyevent(ev):
    trace = document["traceKey"]
    trace.text = f"type: {ev.type}, key: {ev.key}"
    ev.stopPropagation()

document["key_keydown"].bind("keydown", keyevent)
document["key_keypress"].bind("keypress", keyevent)
document["key_keyup"].bind("keyup", keyevent)

ctrlKey

True if the Control key was active when the key event was generated

It is usually used with keypress, to be able to test if Ctrl+<key> was entered, or just <key>

Example

Enter text in the field below, with or without pressing the Ctrl key

Code

from browser import document

def keypress(ev):
    trace = document["traceCtrlKey"]
    trace.text = f"ctrlKey : {ev.ctrlKey}"
    ev.preventDefault()

document["ctrlKey"].bind("keypress", keypress)

Note that ev.preventDefault() is used to avoid the default behaviour of some keyboard shortcuts using the Ctrl key.

code

a string that describes the physical keyboard touch that is hit

this value is the same regardless of the character produced when hitting the key: for instance on an AZERTY keyboard, hitting key A will produce the code "KeyQ"

Example

Put the cursor in the entry fields below and hit random keys.

with keydown

with keypress

with keyup

Code

from browser import document

def keyCode(ev):
    trace = document["traceKeyCode"]
    trace.text = f"event: {ev.type}, code: {ev.code}"
    ev.stopPropagation()

document["codeKeydown"].bind("keydown", keyCode)
document["codeKeypress"].bind("keypress", keyCode)
document["codeKeyup"].bind("keyup", keyCode)

shiftKey

True if the Shift key was active when the key event was generated

It is usually used with keypress, to be able to test if Shift+<key> was entered, or just <key>

Example

Enter text in the field below, with or without pressing the Shift key

Code

from browser import document

def keypress(ev):
    trace = document["traceShiftKey"]
    trace.text = f"shiftKey : {ev.shiftKey}"

document["shiftKey"].bind("keypress", keypress)

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Frequently asked questions

Syntax, keywords and built-in functions

Standard distribution

`import` implementation

Brython packages

Browser interface

Brython-specific built-in modules

Working with Brython

Cookbook

Keyboard events

`DOMEvent` object attributes

Example

Code

Example

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Example

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Browser interface

Brython-specific built-in modules

Working with Brython

Cookbook

Keyboard events

DOMEvent object attributes

Example

Code

Example

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Example

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Example

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`DOMEvent` object attributes