Quantity Field Visibility for Checkbox Product Cards

If you have an add-on product that uses a per unit, tiered, or volume pricing model, and you want to display the quantity field when the checkbox is selected, you can use the following code:

<div data-bind="visible: checked()">

<input type="text" class="input-spinner" min="1" data-bind="value: quantity">

</div>

This is in combination with the checkbox code:

<input type="checkbox" id="additional-option-#{id}#" data-bind="checked: checked">