caption: checkbox
created: 20131024141900000
modified: 20161126081845399
tags: Widgets
title: CheckboxWidget
type: text/vnd.tiddlywiki

! Introduction

The checkbox widget displays an HTML `<input type="checkbox">` element that is dynamically bound to either:

* the presence or absence of a specified tag on a specified tiddler
* the value of a specified field of a specified tiddler

! Content and Attributes

The content of the `<$checkbox>` widget is displayed within an HTML `<label>` element immediately after the checkbox itself. This means that clicking on the content will toggle the checkbox.

|!Attribute |!Description |
|tiddler |Title of the tiddler to manipulate (defaults to the [[current tiddler|Current Tiddler]]) |
|tag |The name of the tag to which the checkbox should be bound |
|invertTag |When set to ''yes'', flips the tag binding logic so that the absence of the tag causes the checkbox to be checked  |
|field |The name of the field to which the checkbox should be bound |
|checked |The value of the field corresponding to the checkbox being checked |
|unchecked |The value of the field corresponding to the checkbox being unchecked |
|default |The default value to use if the field is not defined |
|class |The class that will be assigned to the label element |
|actions |<<.from-version "5.1.14">> A string containing ActionWidgets to be triggered when the checkbox is clicked |

!! Tag Mode

Using the checkbox widget in tag mode requires the ''tag'' attribute to specify the name of the tag. The ''tiddler'' attribute specifies the tiddler to target, defaulting to the current tiddler if not present.

This example creates a checkbox that flips the ''done'' tag on the current tiddler:

```
<$checkbox tag="done">Is it done?</$checkbox>
```

!! Field Mode

Using the checkbox widget in field mode requires the ''field'' attribute to specify the name of the field. The ''checked'' and ''unchecked'' attributes specify the values to be assigned to the field to correspond to its checked and unchecked states respectively. The ''default'' attribute is used as a fallback value if the field is not defined.

This example creates a checkbox that is checked if the field ''status'' is equal to ''open'' and unchecked if the field is equal to ''closed''. If the field is undefined then it defaults to ''closed'', meaning that the checkbox will be unchecked if the ''status'' field is missing.

```
<$checkbox field="status" checked="open" unchecked="closed" default="closed">Is it open?</$checkbox>
```