دسترسپذیری وب (به انگلیسی: Web Accessibility)، به توانایی دستیابی آسان و استفادهٔ برابر از منابع جهانی دادهها و اطلاعات صفحههای وب برای همهٔ کاربران، حتی کاربرانی که به نوعی از معلولیتهای انسانی رنج میبرند، گفته میشود. وبگاههایی که درست طراحی و ویرایش شده و بر مبنای استانداردهای وب برپا شده باشند، برای همه کاربران با هرگونه توانمندی جسمی، به گونهای یکسان در دسترس خواهند بود. برای نمونه صفحهای از وب که با استانداردهای وب طراحی شده و کُد ابرمتن (اچتیامال) آن درست نوشته شده باشد، پیوندهای آن دارای نامگذاری نهفته در کُد، و تصویرهای آن دارای 'متنهای جایگزین تصویر' باشد، به کاربران نابینا کمک میکند تا با نرمافزارهای تبدیل متن به گفتار یا سختافزارهای تبدیل متن به خط بریل، بتوانند به دادههای صفحه دسترسی داشته باشند.
نمونه دیگر صفحههای وب با متنهای بزرگ و خوانا هستند که کاربران با مشکل بینایی اندک را در دستیابی به دادههای وب یاری میدهند، یا پیوندهایی که زیرشان خط کشیده شده و با متن اصلی فرق دارند، کاربرانی که مشکل کوررنگی دارند را یاری میدهند. نمونههای بیشتری پیرامون گفتار دسترسپذیری وب وجود دارد، صفحهای که کُد آن درست و استاندارد نوشته شده باشد، پیوندهایش را میتوان تنها با صفحه کلید، یا دستگاههای ساخته شده برای کاربران ناتوان جسمی رهبری کرد. یا تکه فیلمهایی که زیر کادر نمایش آنها متن یا نشانهای گرافیکی وجود دارد، کاربران ناشنوا و دستهٔ دیگری که مشکل شنوایی دارند را توانمند میکنند. همچنین متنهایی که مرتب و خوانا نوشته شده و با تصویرسازی و عکس همراه باشند، دسترسی به محتوای وب را برای کاربرانی که مشکل دیسلکسیا (به انگلیسی: Dyslexia) و مشکل فراگیری دارند، آسانتر میکنند. هنگامی که طراحی سایت بر پایهٔ دسترسپذیری استوار شده و بر همان مبنا به روز شود، هیچ یک از مشکلهای بالا رخ نداده و در نتیجه دسترسی به محتوای اینترنت برای همه کاربران آسان خواهد بود.
فناوریهای کمکی، برای مرور وب[ویرایش]
کاربرانی که ناتوانیهای جسمی و ذهنی دارند، با سود جستن از فناوریهای زیر، وب را مرور میکنند:
راهنمای طراحی محتوای وب دسترسپذیر[ویرایش]
در سال ۱۹۹۹ میلادی، گروه دسترسپذیری وب (WAI) وابسته به کنسرسیوم جهانی وب، نسخه نخست راهنمای کلی و خط کشیهای زیربنایی دسترسپذیری وب (WCAG ۱.۰) را انتشار دارد. این راهنما اکنون در همه جهان به عنوان راهنمای کلی و خط کشی زیر بنایی دسترسپذیری در وب پذیرفته شدهاست. از سال ۲۰۰۳ تاکنون این گروه بر روی نسخه دوم (WCAG ۲.۰) این راهنما کار میکند که اکنون گامهای واپسین خود را برای به روز بودن، و همگام بودن با استانداردهای صنعتی میپیماید.
دسترسپذیری وب و دولتها[ویرایش]
قانونها و قراردادهای مربوط به دسترسپذیری وب، در کشورهای کانادا، فیلیپین، انگلستان، اسپانیا، استرالیا، سوئد و ایرلند پذیرفته شده و در شماری از این کشورها، برای همه دستگاهها و نهادهای کشوری ضروری است. در کانادا برای نمونه، همه دستگاهای فدرال مجبورند قانونهای مربوط به دسترسپذیری وب و گونه نمایش سایت وب خود را همانند راهنمای کنسرسیوم وب رعایت کنند. افزون بر آن، شماری از این کشورها قانونهای محلی خود را نیز به این راهنما افزودهاند.
Web accessibility is the inclusive practice of ensuring there are no barriers that prevent interaction with, or access to websites, by people with disabilities. When sites are correctly designed, developed and edited, generally all users have equal access to information and functionality.
For example, when a site is coded with semantically meaningful HTML, with textual equivalents provided for images and with links named meaningfully, this helps blind users using text-to-speech software and/or text-to-Braille hardware. When text and images are large and/or enlargeable, it is easier for users with poor sight to read and understand the content. When links are underlined (or otherwise differentiated) as well as colored, this ensures that color blind users will be able to notice them. When clickable links and areas are large, this helps users who cannot control a mouse with precision. When pages are not coded in a way that hinders navigation by means of the keyboard alone, or a single switch access device alone, this helps users who cannot use a mouse or even a standard keyboard. When videos are closed captioned or a sign language version is available, deaf and hard-of-hearing users can understand the video. When flashing effects are avoided or made optional, users prone to seizures caused by these effects are not put at risk. And when content is written in plain language and illustrated with instructional diagrams and animations, users with dyslexia and learning difficulties are better able to understand the content. When sites are correctly built and maintained, all of these users can be accommodated without decreasing the usability of the site for non-disabled users.
The needs that Web accessibility aims to address include:
Assistive technologies used for web browsing
Individuals living with a disability use assistive technologies such as the following to enable and assist web browsing:
Guidelines on accessible web design
Web Content Accessibility Guidelines
On 11 December 2008, the WAI released the WCAG 2.0 as a Recommendation. WCAG 2.0 aims to be up to date and more technology neutral. Though web designers can choose either standard to follow, the WCAG 2.0 have been widely accepted as the definitive guidelines on how to create accessible websites. Governments are steadily adopting the WCAG 2.0 as the accessibility standard for their own websites. In 2012, the Web Content Accessibility Guidelines were also published as an ISO/IEC standard: "ISO/IEC 40500:2012: Information technology -- W3C Web Content Accessibility Guidelines (WCAG) 2.0".
Criticism of WAI guidelines
There has been some criticism of the W3C process, claiming that it does not sufficiently put the user at the heart of the process. There was a formal objection to WCAG's original claim that WCAG 2.0 will address requirements for people with learning disabilities and cognitive limitations headed by Lisa Seeman and signed by 40 organizations and people. In articles such as "WCAG 2.0: The new W3C guidelines evaluated", "To Hell with WCAG 2.0" and "Testability Costs Too Much", the WAI has been criticised for allowing WCAG 1.0 to get increasingly out of step with today's technologies and techniques for creating and consuming web content, for the slow pace of development of WCAG 2.0, for making the new guidelines difficult to navigate and understand, and other argued failings.
In 2011, the Government of Canada began phasing in the implementation of a new set of web standards that are aimed at ensuring government websites are accessible, usable, interoperable and optimized for mobile devices. These standards replace Common Look and Feel 2.0 (CLF 2.0) Standards for the Internet.
The first of these four standards, Standard on Web Accessibility came into full effect on July 31, 2013. The Standard on Web Accessibility follows the Web Content Accessibility Guidelines (WCAG) 2.0 AA, and contains a list of exclusions that is updated annually. It is accompanied by an explicit Assessment Methodology that helps government departments comply. The government also developed the Web Experience Toolkit (WET), a set of reusable web components for building innovative websites. The WET helps government departments build innovative websites that are accessible, usable and interoperable and therefore comply with the government's standards. The WET is open source and available for anyone to use.
As part of the Web Accessibility Initiatives in the Philippines, the government through the National Council for the Welfare of Disabled Persons (NCWDP) board approved the recommendation of forming an adhoc or core group of webmasters that will help in the implementation of the Biwako Millennium Framework set by the UNESCAP.
The Philippines was also the place where the Interregional Seminar and Regional Demonstration Workshop on Accessible Information and Communications Technologies (ICT) to Persons with Disabilities was held where eleven countries from Asia - Pacific were represented. The Manila Accessible Information and Communications Technologies Design Recommendations was drafted and adopted in 2003.
In Spain, UNE 139803 is the norm entrusted to regulate web accessibility. This standard is based on Web Content Accessibility Guidelines 1.0.
In Sweden, Verva, the Swedish Administrative Development Agency is responsible for a set of guidelines for Swedish public sector web sites. Through the guidelines, web accessibility is presented as an integral part of the overall development process and not as a separate issue. The Swedish guidelines contain criteria which cover the entire lifecycle of a website; from its conception to the publication of live web content. These criteria address several areas which should be considered, including:
An English translation was released in April 2008: Swedish National Guidelines for Public Sector Websites. The translation is based on the latest version of Guidelines which was released in 2006.
In December 2010 the UK released the standard BS 8878:2010 Web accessibility. Code of practice. This standard effectively supersedes PAS 78 (pub. 2006). PAS 78, produced by the Disability Rights Commission and sable by disabled people. The standard has been designed to introduce non-technical professionals to improved accessibility, usability and user experience for disabled and older people. It will be especially beneficial to anyone new to this subject as it gives guidance on process, rather than on technical and design issues. BS 8878 is consistent with the Equality Act 2010 and is referenced in the UK government’s e-Accessibility Action Plan as the basis of updated advice on developing accessible online services. It includes recommendations for:
BS 8878 is intended for anyone responsible for the policies covering web product creation within their organization, and governance against those policies. It additionally assists people responsible for promoting and supporting equality and inclusion initiatives within organizations and people involved in the procurement, creation or training of web products and content. A summary of BS 8878 is available to help organisations better understand how the standard can help them embed accessibility and inclusive design in their business-as-usual processes.
Web Content Accessibility Guidelines in Japan were established in 2004 as JIS (Japanese Industrial Standards) X 8341-3. JIS X 8341-3 was revised in 2010 to adopt WCAG 2.0. The new version, published by the Web Accessibility Infrastructure Commission (WAIC), has the same four principles, 12 guidelines, and 61 success criteria as WCAG 2.0 has.
Essential components of web accessibility
The accessibility of websites relies on the cooperation of eight components:
These components interact with each other to create an environment that is accessible to people with disabilities.
Guidelines for different components
Authoring Tool Accessibility Guidelines (ATAG)
Web Content Accessibility Guidelines (WCAG)
User Agent Accessibility Guidelines (UAAG)
Web accessibility legislation
Because of the growth in internet usage and its growing importance in everyday life, countries around the world are addressing digital access issues through legislation. One approach is to protect access to websites for people with disabilities by using existing human or civil rights legislation. Some countries, like the U.S., protect access for people with disabilities through the technology procurement process. It is common for nations to support and adopt the Web Content Accessibility Guidelines (WCAG) 2.0 by referring to the guidelines in their legislation.
In 2000, an Australian blind man won a $20,000 court case against the Sydney Organizing Committee of the Olympic Games (SOCOG). This was the first successful case under Disability Discrimination Act 1992 because SOCOG had failed to make their official website, Sydney Olympic Games, adequately accessible to blind users. The Human Rights and Equal Opportunity Commission (HREOC) also published World Wide Web Access: Disability Discrimination Act Advisory Notes. All Governments in Australia also have policies and guidelines that require accessible public websites; Vision Australia maintain a complete list of Australian web accessibility policies.
In Brazil, the federal government published a paper with guidelines for accessibility on 18 January 2005, for public reviewing. On 14 December of the same year, the second version was published, including suggestions made to the first version of the paper. On 7 May 2007, the accessibility guidelines of the paper became compulsory to all federal websites. The current version of the paper, which follows the WCAG 2.0 guidelines, is named e-MAG, Modelo de Acessibilidade de Governo Eletrônico (Electronic Government Accessibility Model), and is maintained by Brazilian Ministry of Planning, Budget, and Management.
The paper can be viewed and downloaded at its official website.
On 26 October 2016, the European Parliament accepted a directive that requires that the websites and mobile apps of public sector bodies be accessible. The relevant accessibility requirements are described in the European standard EN 301 549 V1.1.2 (published by ETSI). EU member states are expected to bring into force by 23 September 2018 laws and regulations that enforce the relevant accessibility requirements. Websites of public sector bodies should comply by 23 September 2018; mobile apps by 23 June 2021. Some categories of websites and apps are excepted from the directive, for example "websites and mobile applications of public service broadcasters and their subsidiaries".
The European Commission's "Rolling Plan for ICT Standardisation 2017" notes that ETSI standard EN 301 549 V1.1.2 will need to be updated to add accessibility requirements for mobile applications and evaluation methodologies to test compliance with the standard.
In Ireland, the Disability Act 2005 requires that where a public body communicates in electronic form with one or more persons, the contents of the communication must be, as far as practicable, "accessible to persons with a visual impairment to whom adaptive technology is available" (Section 28(2)). The National Disability Authority has produced a Code of Practice giving guidance to public bodies on how to meet the obligations of the Act. This is an approved code of practice and its provisions have the force of legally binding statutory obligations. It states that a public body can achieve compliance with Section 28(2) by "reviewing existing practices for electronic communications in terms of accessibility against relevant guidelines and standards", giving the example of "Double A conformance with the Web Accessibility Initiative's (WAI) Web Content Accessibility Guidelines (WCAG)".
The Israeli Ministry of Justice recently published regulations requiring Internet websites to comply with Israeli standard 5568, which is based on the W3C Web Content Accessibility Guidelines 2.0. The main differences between the Israeli standard and the W3C standard concern the requirements to provide captions and texts for audio and video media. The Israeli standards are somewhat more lenient, reflecting the current technical difficulties in providing such captions and texts in Hebrew.
In Italy, web accessibility is ruled by the so-called "Legge Stanca" (Stanca Act), formally Act n.4 of 9 January 2004, officially published on the Gazzetta Ufficiale on 17 January 2004. The original Stanca Act was based on the WCAG 1.0. On 20 March 2013 the standards required by the Stanca Act were updated to the WCAG 2.0.
In Norway, web accessibility is a legal obligation under the Act June 20, 2008 No 42 relating to a prohibition against discrimination on the basis of disability, also known as the Anti-discrimination Accessibility Act. The Act went into force in 2009, and the Ministry of Government Administration, Reform and Church Affairs [Fornyings-, administrasjons- og kirkedepartementet] published the Regulations for universal design of information and communication technology (ICT) solutions [Forskrift om universell utforming av informasjons- og kommunikasjonsteknologiske (IKT)-løsninger] in 2013. The regulations require compliance with Web Content Accessibility Guidelines 2.0 (WCAG 2.0) / NS / ISO / IEC 40500: 2012, level A and AA with some exceptions. The Norwegian Agency for Public Management and eGovernment (Difi) is responsible for overseeing that ICT solutions aimed at the general public are in compliance with the legislative and regulatory requirements.
In the UK, the Equality Act 2010 does not refer explicitly to website accessibility, but makes it illegal to discriminate against people with disabilities. The Act applies to anyone providing a service; public, private and voluntary sectors. The Code of Practice: Rights of Access – Goods, Facilities, Services and Premises document published by the government's Equality and Human Rights Commission to accompany the Act does refer explicitly to websites as one of the "services to the public" which should be considered covered by the Act.
In the United States, Section 508 Amendment to the Rehabilitation Act of 1973 requires all Federal agencies' electronic and information technology to be accessible to those with disabilities. Both members of the public and federal employees have the right to access this technology, such as computer hardware and software, websites, phone systems, and copiers. Also, Section 504 of the Rehabilitation Act prohibits discrimination on the basis of disability for entities receiving federal funds and has been cited in multiple lawsuits against organizations such as hospitals that receive federal funds through medicare/medicaid.
In addition, Title III of the Americans with Disabilities Act (ADA) prohibits discrimination on the basis of disability. There is some debate on the matter, multiple courts and the U.S. Department of Justice have taken the position that the ADA requires website and app operators and owners to take affirmative steps to make their websites and apps accessible to disabled persons and compatible with common assistive technologies such as the JAWS screen reader, while other courts have taken the position that the ADA does not apply online. The U.S. Department of Justice has endorsed the WCAG2.0AA standard as an appropriate standard for accessibility in multiple settlement agreements.
Website accessibility audits
A growing number of organizations, companies and consultants offer website accessibility audits. These audits, a type of system testing, identify accessibility problems that exist within a website, and provide advice and guidance on the steps that need to be taken to correct these problems.
A range of methods are used to audit websites for accessibility:
Each of these methods has its strengths and weaknesses:
Ideally, a combination of methods should be used to assess the accessibility of a website.
Remediating inaccessible websites
Once an accessibility audit has been conducted, and accessibility errors have been identified, the errors will need to be remediated in order to ensure the site is compliant with accessibility errors. The traditional way of correcting an inaccessible site is to go back into the source code, reprogram the error, and then test to make sure the bug was fixed. If the website is not scheduled to be revised in the near future, that error (and others) would remain on the site for a lengthy period of time, possibly violating accessibility guidelines. Because this is a complicated process, many website owners choose to build accessibility into a new site design or re-launch, as it can be more efficient to develop the site to comply with accessibility guidelines, rather than to remediate errors later.
Accessible Web applications and WAI-ARIA
Standards and guidelines