link aware progressive disclosure

toggle-controls.js

// modified from https://adactio.com/journal/10365
// Licensed under a CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
// http://creativecommons.org/publicdomain/zero/1.0/
(function (win, doc) {
	'use strict';
	if (!doc.querySelectorAll || !win.addEventListener) {
		// doesn't cut the mustard.
		return;
	}

	// show
	function showToggle(toggle, togglecontent){
		togglecontent.setAttribute('aria-hidden', 'false');
		toggle.setAttribute('aria-expanded', 'true');
	}

	// hide
	function hideToggle(toggle, togglecontent){
		togglecontent.setAttribute('aria-hidden', 'true');
		toggle.setAttribute('aria-expanded', 'false');
	}


	// set toggle
	function setToggle(){

		for (var toggles = doc.querySelectorAll('[aria-controls]'), index = 0, toggle; (toggle = toggles[index]); ++index) {
			var toggleID = toggle.getAttribute('aria-controls');
			if (doc.getElementById(toggleID)) {
				var togglecontent = doc.getElementById(toggleID),
				id = location.href.match(/#((?:#|%23)?)(.+)/) || [0,'',''],
				islinked = false;

				/* find if togglecontent or any children are fragment targets or fragmentioned */

				if(toggleID == id[1]+id[2] || togglecontent.hasAttribute("fragmention") ){
					islinked = true;
				}else{
					try{
						islinked = togglecontent.querySelectorAll('#'+id[1]+id[2]).length;
					}catch(e){
						islinked = togglecontent.querySelectorAll('[fragmention]').length;
					}
				}

				if(islinked){
					showToggle(toggle,togglecontent);

				}else{

					hideToggle(toggle,togglecontent);
					togglecontent.setAttribute('tabindex', '-1');
				}
			toggle.setAttribute('aria-hidden', 'false');

			}
		}
	}

	// toggle show and hide
	function toggle(ev) {
		ev = ev || win.event;
		var target = ev.target || ev.srcElement;
		if (target.hasAttribute('aria-controls')) {
			var toggleID = target.getAttribute('aria-controls');
			if (doc.getElementById(toggleID)) {
				ev.preventDefault();
				var togglecontent = doc.getElementById(toggleID);
				if (togglecontent.getAttribute('aria-hidden') == 'true') {
					showToggle(target, togglecontent);
					// togglecontent.focus(); https://github.com/edenspiekermann/a11y-toggle/issues/10
				} else {
					hideToggle(target, togglecontent);
				}
			}
		}
	}
	doc.addEventListener('click', toggle, false);

	for(var links = doc.querySelectorAll('a'), index = 0, link; (link = links[index]); ++index) {
		link.addEventListener('click', setToggle, false);
	}

	// add listeners for hashchange and readystate
	win.addEventListener("hashchange", setToggle, false);
	doc.addEventListener('readystatechange', setToggle, false);

	setToggle();

}(this, this.document));