Checkbox multicard select, basic variant

Notes for developers

When creating a set of multicard select checkboxes, they must be contained within a single fieldset where the legend is the question/title for the whole group. Within a group of checkboxes the name attribute must be unique to the form, and the id attribute must be unique to the page. Furthermore, sets of cards should be contained as list items within a ul element in order to retain a link between them and to assist users taking advantage of screenreaders.

When disabling form elements, do not solely rely on the is-disabled class, but ensure that the disabled attribute is also set on the relevant form element or input. If an entire set of form elements is to be disabled, the is-disabled class and disabled attribute should be added directly to the fieldset instead, and not to each individual element within it. However if only one element from the set is disabled, then the class and attribute should be applied to that element only.

The is-invalid class can also be added alongside is-disabled to fade the opacity of the card and display a message on an overlay; this message is set within the m-card-disabled span following the a-checkbox__ui span.

If the native form validation needs to be disabled, set the novalidate attribute on the form.

Aria usage for errors and help text

To aid screen reader users in completing forms without error and also with understanding and fixing any errors that have occured, some additional aria attributes are now recommended to be applied across all form fields/rows.

All form row help, explanatory text, form row instructions and form row errors must have a unique id assigned to them and be appropriately linked to either the individual form input or the form row using aria-describedby. This ensures that the help text is read out immediately on focus of the form input/fieldset. When there is more that one item that requires referencing within the aria-describedby attribute the id values must be supplied in the form of a space separated list. For example if there is an error with id of 'err1' and help text with id of 'help1' the value for the aria-describedby attribute would be 'err1 help1'.

All inline form error messages should start with the hidden text 'Error: ' so that when read by out by a screen reader it is immediately clear that the text being read is an error message.

All erroring form fields (or fieldset if a group or radios/checkboxes) must have aria-invalid="true" set on them, ensuring that when a user focus' on an errored form field, the field will be announced as invalid, so the user is then aware that there in an issue that requires fixing.

When linking help or errors, or even adding aria-invalid to the markup careful consideration must be taken as to where it is most appropriate to apply the value. The following rules should be used to decide where the attribute(s) should be applied.

• Single form field - All attributes should be applied directly to that form field
• Group of form fields but only one in error or help text applies to only one - Apply the attribute(s) to the only field in error or where the help text applies
• Group of form field where all in error or the help text applies to all - Apply the attribute(s) to the groups surrounding fieldset (form row)

There may situations where more than one of these rules applies to the overall form row for example a date range where the instruction text applies to both fields so should be linked to the fieldset for the date range but one of the two fields is in error so the error should be linked to just that field not to the fieldset.

Important messages

To help those using assistive technologies, make sure that success/error messages which need to be announced to users have their aria attributes updated to role="alert" and/or aria-live="assertive".

Accent colours

Do not use within areas with t-card-accent classes applied as this could cause the font colours to display incorrectly.

Data module

Adding the data-module="o-card-select" allows the maximum number of checkboxes which it is possible to select to be restricted, displaying a count and adding an overlay with a warning message when this limit is reached.

The message displayed above the card row can be customised to suit requirements. The child span within the .o-card-select__selected-message > p tag is populated by JavaScript to display the appropriate numer of cards selected, followed by '/' followed by the maximum number of cards permitted (set in the data-max attribute), followed by the value set in the data-selected attribute, for example '2 / 2 selected'. If JavaScript is not present, only the basic message will be displayed.

The message which appears on the overlay when the maximum number of cards has been selected is set via the locale settings:

en: {
	oCardSelect : {
		maxMessage : 'Maximum reached - Please deselect an option to proceed',
	},
},

For more information on this, see our page on how to change locale settings within JavaScript.

The overlay and message can be disabled if required - add the data-overlay="off" attribute to achieve this.

Using autocomplete

Users appreciate when websites save them time by automatically filling common fields like names, email addresses and other frequently used fields, plus it helps to reduce potential input errors, especially on virtual keyboards and small devices.

Browsers use many methods to determine which fields they can auto-populate based on previously specified data by the user, and you can give hints to the browser by providing both the name attribute and the autocomplete attribute on each input element.

Further details can be found in the developer notes on the form introduction page.

Controling the checkbox multicard select component programatically

Checkbox multicard select can be controlled programatically to deselect all or to select/deselect a set of multicard select cards. The following methods are available for use:

For example:

document.addEventListener( 'frameworkready', function () {
	FRAMEWORK.require([ 'blocks/o-card-select' ], function ( oCardSelectModule ) {
		var oCardSelectEl = document.querySelector( '#multicardGroupId' ),
			oCardSelectInstance = oCardSelectModule.initInstance( oCardSelectEl );		oCardSelectInstance.select( [ '#inputId1', '#inputId2' ] );
	});
});

Other information

The entire card is clickable; for this reason, the contents within the card have been converted to span tags to ensure the code validates. Take care when adding additional elements to ensure this principle is followed.

Checkbox multicard select rows must not be nested inside other cards with a dark accent colour background, as the results could be unpredicatble.

Extension component

This component forms part of the 'forms-extended-a' extension and so requires an additional stylesheet to be loaded in order to be used; include the following code in the header of your page to attach the relevant additional stylesheet:

<link media="all" href="./assets/[ theme type ]/[ release version ]/[ organisation ]/[ theme name ]/css/forms-extended-a.css" rel="stylesheet" />

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Notes for testers

• Ensure that all checkboxes have a related label. It should be really clear which label applies to which checkbox by using background shading to group the label and the checkbox together.
• Ensure carousel controls and movement remain fluent regardless of browser type and / or orientation. Check further carousel functionality against standard expectations laid out on the card carousel documentation page.

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Classes overview

The following table gives you a quick overview of the CSS classes that can be applied.

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Keyboard operations

TAB

Tabbing to an checkbox input should make the input clearly visually different so that the focus point on the page is obvious to the user.

CURSOR KEYS

With focus on the checkbox, pressing SPACE will select/deselect the checkbox.