https://mathinsight.org/static/js/yaml-focusfix.js

1/**
2 * "Yet Another Multicolumn Layout" - YAML CSS Framework
3 *
4 * (en) Workaround for IE8 und Webkit browsers to fix focus problems when using skiplinks
5 * (de) Workaround für IE8 und Webkit browser, um den Focus zu korrigieren, bei Verwendung von Skiplinks
6 *
7 * @note			inspired by Paul Ratcliffe's article
8 *					http://www.communis.co.uk/blog/2009-06-02-skip-links-chrome-safari-and-added-wai-aria
9 *                  Many thanks to Mathias Schäfer (http://molily.de/) for his code improvements
10 *
11 * @copyright       Copyright 2005-2012, Dirk Jesse
12 * @license         CC-BY 2.0 (http://creativecommons.org/licenses/by/2.0/),
13 *                  YAML-CDL (http://www.yaml.de/license.html)
14 * @link            http://www.yaml.de
15 * @package         yaml
16 * @version         4.0+
17 * @revision        $Revision: 617 $
18 * @lastmodified    $Date: 2012-01-05 23:56:54 +0100 (Do, 05 Jan 2012) $
19 */
20
21(function () {
22	var YAML_focusFix = {
23		skipClass : 'ym-skip',
24
25		init : function () {
26			var userAgent = navigator.userAgent.toLowerCase();
27			var	is_webkit = userAgent.indexOf('webkit') > -1;
28			var	is_ie = userAgent.indexOf('msie') > -1;
29
30			if (is_webkit || is_ie) {
31				var body = document.body,
32					handler = YAML_focusFix.click;
33				if (body.addEventListener) {
34					body.addEventListener('click', handler, false);
35				} else if (body.attachEvent) {
36					body.attachEvent('onclick', handler);
37				}
38			}
39		},
40
41		trim : function (str) {
42			return str.replace(/^\s\s*/, '').replace(/\s\s*$/, '');
43		},
44
45		click : function (e) {
46			e = e || window.event;
47			var target = e.target || e.srcElement;
48			var a = target.className.split(' ');
49
50			for (var i=0; i < a.length; i++) {
51				var cls = YAML_focusFix.trim(a[i]);
52				if ( cls === YAML_focusFix.skipClass) {
53					YAML_focusFix.focus(target);
54					break;
55				}
56			}
57		},
58
59		focus : function (link) {
60			if (link.href) {
61				var href = link.href,
62					id = href.substr(href.indexOf('#') + 1),
63					target = document.getElementById(id);
64				if (target) {
65					target.setAttribute("tabindex", "-1");
66					target.focus();
67				}
68			}
69		}
70	};
71	YAML_focusFix.init();
72})();