Joomla! Programmers Documentation

The checkbox form field type provides a single checkbox. If the parameter has a saved value this is selected when the page is first loaded. If not, the default value (if any) is selected.

• type (mandatory) must be checkbox.
• name (mandatory) is the unique name of the field.
• label (mandatory) (translatable) is the field html label.
• value (optional) is the value of the parameter if this checkbox is set (usually 1).
• checked (optional) should be set to 1 to check the checkbox by default or 0 if not.
• description (optional) (translatable) is the field description.
• class (optional) allows you set a css class for display. If omitted this will default to 'inputbox'
• multiple (optional) if set to true allows multiple items to be selected at the same time. Set to false to allow single selection.

Implemented by: libraries/src/Form/Field/CheckboxField.php

Example XML parameter definition¶

<field
        name="show_title" 
        type="checkbox" 
        label="Show title" 
        description="Show the title of the item" 
        value="1"
/>

Example XML parameter definition (with Checkbox checked)¶

<field
        name="show_title" 
        type="checkbox" 
        label="Show title" 
        description="Show the title of the item" 
        value="1"
        checked="1"
/>

:::warning Special care needs to be taken with saving a checkbox from a form!! This is a common mistake. You see, on saving a form with a checkbox that is unchecked, there is no variable for it in the POST information and this is standard browser behaviour.

See Discussion on this page for some suggestions for how you might like to handle this. :::