accessibility-developer-tools
Version:
This is a library of accessibility-related testing and utility code.
61 lines (56 loc) • 2.42 kB
JavaScript
// Copyright 2012 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
goog.require('axs.AuditRules');
goog.require('axs.browserUtils');
goog.require('axs.constants.Severity');
goog.require('axs.dom');
goog.require('axs.utils');
/**
* This audit checks for elements that are focusable but invisible or obscured by another element.
*/
axs.AuditRules.addRule({
name: 'focusableElementNotVisibleAndNotAriaHidden',
heading: 'These elements are focusable but either invisible or obscured by another element',
url: 'https://github.com/GoogleChrome/accessibility-developer-tools/wiki/Audit-Rules#ax_focus_01',
severity: axs.constants.Severity.WARNING,
relevantElementMatcher: function(element) {
var isFocusable = axs.browserUtils.matchSelector(
element, axs.utils.FOCUSABLE_ELEMENTS_SELECTOR);
if (!isFocusable)
return false;
if (element.tabIndex >= 0)
return true;
// Ignore elements which have negative tabindex and an ancestor with a
// widget role, since they can be accessed neither with tab nor with
// a screen reader
for (var parent = axs.dom.parentElement(element); parent != null;
parent = axs.dom.parentElement(parent)) {
if (axs.utils.elementIsAriaWidget(parent))
return false;
}
// Ignore elements which have a negative tabindex and no text content,
// as they will be skipped by assistive technology
var textAlternatives = axs.properties.findTextAlternatives(element, {});
if (textAlternatives === null || textAlternatives.trim() === '')
return false;
return true;
},
test: function(element, flags) {
if (flags.hidden)
return false;
element.focus();
return !axs.utils.elementIsVisible(element);
},
code: 'AX_FOCUS_01'
});