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https://github.com/nico3333fr/van11y-accessible-hide-show-aria

ES2015 accessible hide-show system (collapsible regions), using ARIA
https://github.com/nico3333fr/van11y-accessible-hide-show-aria

a11y accessibility aria collapsible-regions es2015

Last synced: 15 days ago
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ES2015 accessible hide-show system (collapsible regions), using ARIA

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# Van11y Accessible hide/show (collapsible regions) using ARIA



Van11y



This script will transform a simple list of Hx/contents into shiny and accessible hide/show – collapsible regions – using ARIA.



The demo is here: https://van11y.net/downloads/hide-show/demo/index.html



Website is here: https://van11y.net/accessible-hide-show/



La page existe aussi en français : https://van11y.net/fr/panneaux-depliants-accessibles/



## How it works



Basically, it transforms this:

```html

Lorem dolor si amet




   here the hidden content



```

Into this:

```html



  Lorem dolor si amet





   here the hidden content



```

Attribute values are generated on-the-fly (```data-controls="expand_1"```, ```id="expand_1"```, ```data-labelledby="label_expand_1"```), no need to worry about it.



The script is launched when the page is loaded. If you need to execute it on AJAX-inserted content, you may use for example on ```
your expand source
```:



```js

var my_expand = van11yAccessibleHideShowAria();

my_expand.attach(document.getElementById('newContent'));

```



## How to use it



__Download the script__



You may use npm command: ```npm i van11y-accessible-hide-show-aria```.

You may also use bower: ```bower install van11y-accessible-hide-show-aria```.



__Conventions__



Please follow this convention (the conventions may be adapted to your needs, see in bonuses):

```html

Lorem dolor si amet




   here the hidden content



```

For accessibility reasons, you shall add ```class="js-expandmore"``` on an ```Hx``` (h1, h2, h3, etc.).

Elements that have ```js-expandmore``` and ```js-to_expand``` classes must be adjacent.



Then use the script, it will do the rest.



__Styles needed to work__



The minimal style needed is:

```css

.js-to_expand[aria-hidden=true],

.js-to_expand[data-hidden=true] {

  display: none;

}

```

However, as the plugin adds a button into a ```Hx```, you will have to style this case. Here is an example:

```css

.expandmore__button {

  background: none;

  font-size: inherit;

  color: inherit;

}

/* optional */

.expandmore__button:before,

.expandmore__button:before {

  content : '+ ';

}

.expandmore__button[aria-expanded=true]:before,

.expandmore__button[data-expanded=true]:before {

  content : '- ';

}

```



## How to create different styles?



It is possible and very simple, you may use the attribute ```data-hideshow-prefix-class=""``` like this:

```html

Lorem dolor si amet




   here the hidden content



```

It will prefix generated classes, ```-expandmore__button``` and ```-expandmore__to_expand```, like this:

```html



 

  Lorem dolor si amet

 





 here the hidden content



```



The script will prefix all classes, so you will able to style elements as you want. If you don’t use it, the script won’t mind.



## Bonuses



__Opened by default__



No problem, it is possible and very simple, use the class ```is-opened``` on:

```html

Lorem dolor si amet




   here the hidden content



```

The script will detect it, and make it open by default. As simple as one copy/paste.



__Animations__



No problem, it is possible using some CSS transitions. You have to keep in mind several things to keep it accessible:



- You can’t animate the display property, and height property might be complicated too to animate.

- So you can’t use display: none; to hide a content (even for assistive technologies).

- You have to set up visibility to visible or hidden to show/hide a content.

- Basically, you should animate max-height, opacity (if needed), and use visibility to hide content to assistive technology.



If you have clicked on this section, you might have noticed the animation. Let’s assume we are using this source:

```html

Bonus: some animations?


 


 …

 


```

So here is the CSS code (unprefixed):

```css

/* This is the opened state */

.animated-expandmore__to_expand {

 display: block;

 overflow: hidden;

 opacity: 1;

 transition: visibility 0s ease, max-height 2s ease, opacity 2s ease ;

 max-height: 80em;

 /* magic number for max-height = enough height */

 visibility: visible;

 transition-delay: 0s;

}

/* This is the hidden state */

[data-hidden=true].animated-expandmore__to_expand {

 display: block;

 max-height: 0;

 opacity: 0;

 visibility: hidden;

 transition-delay: 2s, 0s, 0s;

}

```

Here is the trick: from “hidden” to “visible” state, visibility is immediately set up to visible, and max-height/opacity are “normally” animated.



From “visible” to “hidden” state, the visibility animation is delayed. So the content will be immediately hidden… at the end of the animation of max-height/opacity.



__Default config__



```js

const CONFIG = {

    HIDESHOW_EXPAND: 'js-expandmore',

    HIDESHOW_BUTTON_EXPAND: 'js-expandmore-button',

    HIDESHOW_BUTTON_EXPAND_STYLE: 'expandmore__button',

    HIDESHOW_BUTTON_LABEL_ID: 'label_expand_',



    DATA_PREFIX_CLASS: 'data-hideshow-prefix-class',



    HIDESHOW_BUTTON_EMPTY_ELEMENT_SYMBOL: 'expandmore__symbol',

    HIDESHOW_BUTTON_EMPTY_ELEMENT_TAG: 'span',

    ATTR_HIDESHOW_BUTTON_EMPTY_ELEMENT: 'aria-hidden',



    HIDESHOW_TO_EXPAND_ID: 'expand_',

    HIDESHOW_TO_EXPAND_STYLE: 'expandmore__to_expand',



    /*

     recommended settings by a11y expert

    */

    ATTR_CONTROL: 'data-controls',

    ATTR_EXPANDED: 'aria-expanded',

    ATTR_LABELLEDBY: 'data-labelledby',

    ATTR_HIDDEN: 'data-hidden',



    IS_OPENED_CLASS: 'is-opened',



    DISPLAY_FIRST_LOAD: 'js-first_load',

    DISPLAY_FIRST_LOAD_DELAY: '1500',

    ...config

};

```



If you need to use another configuration, you may call the plugin like this:



```js

var other_expand = van11yAccessibleHideShowAria({

     HIDESHOW_EXPAND: 'js-expandmore2',

     DATA_PREFIX_CLASS: 'data-hideshow-prefix-class2'

    });

other_expand.attach();

```



__ARIA attributes or data attributes?__



No problem. At the beginning of the plugin, you can set up the attributes you need for your special case.

```js

ATTR_CONTROL: 'data-controls',

ATTR_EXPANDED: 'aria-expanded',

ATTR_LABELLEDBY: 'data-labelledby',

ATTR_HIDDEN: 'data-hidden',

```

However, the default settings are recommended by accessibility experts.



If you need to update, you can do it anyway, the plugin will adapt itself. Example:



```js

var my_expand = van11yAccessibleHideShowAria({

    ATTR_CONTROL: 'aria-controls',

    ATTR_EXPANDED: 'aria-expanded',

    ATTR_LABELLEDBY: 'aria-labelledby',

    ATTR_HIDDEN: 'aria-hidden',

    });

my_expand.attach();

```



Of course, you will have to update your CSS by using the good attributes.