caption: keyboard
created: 20140302192136805
modified: 20210612101618855
tags: Widgets
title: KeyboardWidget
type: text/vnd.tiddlywiki

! Introduction

The keyboard widget allows ActionWidgets to be triggered by specific key combinations. There is also a shorthand for generating [[Messages]] via the `message` and `param` attributes.

! Content and Attributes

The content of the `<$keyboard>` widget is rendered normally. The keyboard shortcuts only take effect when the focus is within the contained content.

|!Attribute |!Description |
|actions |A string containing ActionWidgets to be triggered when the key combination is detected<br><<.from-version "5.2.0">> The variables: ''event-key'', ''event-code'' and ''modifier'' are available for the actions |
|message |The title of the [[WidgetMessage|Messages]] to generate |
|param |The parameter to be passed with the [[WidgetMessage|Messages]] |
|key |Key string identifying the key(s) to be trapped (see below) |
|class |A CSS class to be assigned to the generated HTML DIV element |
|tag|<<.from-version "5.1.14">> The html element the widget creates to capture the keyboard event, defaults to:<br>» `span` when parsed in inline-mode<br>» `div` when parsed in block-mode|

! Variables

<<.from-version "5.2.0">> The following variables are made available to the actions:

|!Variables |!Description |
|`event-key` |The <<.var event-key>> variable contains the character, if possible. eg: `1`. You can experiment with some settings at: [[Key Codes (Example)]] |
|`event-code` |The <<.var event-code>> variable contains a character description. eg:  `Digit1` instead of `1`. Or `Space` instead of an empty string ` `, which is hard to see|
|`event-key-descriptor` |The <<.var event-key-descriptor>> variable is available if the keyboard event captured was configured using a [[keyboard shortcut descriptor|Keyboard Shortcut Descriptor]] of the form `((my-shortcut))` which references a configuration tiddler. |
|`modifier` |The [[modifier Variable]] contains the Modifier Key held during the event (can be <kbd>normal</kbd>, <kbd>ctrl</kbd>, <kbd>shift</kbd>, <kbd>alt</kbd> or combinations thereof) |

! Key Strings

Key strings are made up of one or more key specifiers separated by spaces. Each key specifier is zero or more of the modifiers <kbd>alt</kbd>, <kbd>shift</kbd>, <kbd>ctrl</kbd> or <kbd>meta</kbd> followed by the name of a key, all joined with "+" plus or "-" minus symbols. Key names are either the letter or digit printed on the key (eg "a" or "1"), or one of the special keys <kbd>backspace</kbd>, <kbd>tab</kbd>, <kbd>enter</kbd> or <kbd>escape</kbd>.

<$railroad text="""
[: {
   ("alt" | "shift" | "ctrl" |: "meta" ) +("+" | "-") 
	 }
	 "+" 
]
( "<a-z,0-9>" | "backspace" |: "tab" | "enter" | "escape" )
"""/>

For example:

```
A
shift+A
shift+escape
ctrl+enter
ctrl+shift+alt+A
```

! More Info

<<list-links "[tag[KeyboardWidget]]">>