accessibility-developer-tools
Version:
This is a library of accessibility-related testing and utility code.
72 lines (69 loc) • 2.59 kB
JavaScript
// Copyright 2014 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.utils');
/**
* This audit checks for duplicate IDs in the DOM.
*/
axs.AuditRules.addRule({
name: 'duplicateId',
heading: 'Any ID referred to via an IDREF must be unique in the DOM',
url: 'https://github.com/GoogleChrome/accessibility-developer-tools/wiki/Audit-Rules#ax_html_02',
severity: axs.constants.Severity.SEVERE,
opt_requires: {
idRefs: true
},
/**
* @this {axs.AuditRule}
*/
relevantElementMatcher: function(element, flags) {
if (flags.idrefs.length && !flags.hidden) {
this.relatedElements.push({
element: element,
flags: flags
});
}
if (element.hasAttribute('id')) {
return true;
}
return false;
},
/**
* @this {axs.AuditRule}
*/
isRelevant: function(element, flags) {
var id = element.id;
var level = flags.level;
return this.relatedElements.some(function(related) {
var idrefs = related.flags.idrefs;
return related.flags.level === level && idrefs.indexOf(id) >= 0;
});
},
test: function(element) {
/*
* Checks for duplicate IDs within the context of this element.
* This is not a pure a11y check however IDREF attributes in ARIA and HTML (label 'for', td 'headers)
* depend on IDs being correctly implemented.
* Because this audit is noisy (in practice duplicate IDs are not unusual and often harmless)
* we limit this audit to IDs which are actually referred to via any IDREF attribute.
*/
var id = element.id;
var selector = '[id=\'' + id.replace(/'/g, '\\\'') + '\']';
var elementsWithId = element.ownerDocument.querySelectorAll(selector);
return (elementsWithId.length > 1);
},
code: 'AX_HTML_02'
});