- Open Access
Web accessibility support for visually impaired users using link content analysis
© Iwata et al.; licensee Springer. 2013
- Received: 5 November 2012
- Accepted: 1 March 2013
- Published: 18 March 2013
Web pages are used for a variety of purposes. End users must understand dynamically changing content and sequentially follow page links to find desired material, requiring significant time and effort. However, for visually impaired users using screen readers, it can be difficult to find links to web pages when link text and alternative text descriptions are inappropriate. Our method supports the discovery of content by analyzing 8 categories of link types, and allows visually impaired users to be aware of the content represented by links in advance. This facilitates end users access to necessary information on web pages. Our method of classifying web page links is therefore effective as a means of evaluating accessibility.
- Web page link
- Link classification
Web accessibility, which refers to web pages being easily usable by all end users, is also regarded as important. There are many guidelines pertaining to accessibility (Section 508 Homepage 2011; Web Content Accessibility Guidelines (WCAG) 2008). In particular, visually impaired users often use support software such as screen readers (Freedom Scientific Inc. 2011). Screen readers are software programs that read aloud the material displayed on screens.
However, the current degree of support for visually impaired users is inadequate. When end users want to find web pages, they must often follow a number of links. It is sometimes difficult for visually impaired users using screen readers to find web page links. Screen readers usually read both link text and the alternative text associated with images. It is difficult for visually impaired users to locate a link when the link text or alternative text descriptions are not appropriate. It is preferable for visually impaired users to know the type of content associated with a link before they actually follow or click on it. For example, links to advertisements may redirect the user to other sites. Visually impaired users cannot know that they have navigated to another site until the screen reader begins to read the content aloud. There are tools and methods to identify problems faced by visually impaired users when they access web pages. However, the purpose of these methods is to reveal the problems to web page designers, and thus it is necessary for end users to wait until the pages are finally modified.
Therefore, we propose a method of automatically distinguishing categories of links on web pages. Web pages are analyzed by extracting links from the pages’ HTML sources. Visually impaired users can be aware of the content represented by each link beforehand, and end users can minimize the time spent following unnecessary links.
In the context of IT (Information Technology), accessibility refers to the degree to which services or software are easily usable, particularly by the elderly and disabled. The accessibility of web pages is called “web accessibility”.
Definition of web accessibility
Web accessibility refers to construction of a web site such that all users can access its information, regardless of their age or physical limitations, and can easily navigate its environment. Visually impaired users often use screen readers. A screen reader is an application that converts onscreen text into speech. When this type of software reads text containing a web site link, it generally reads both the text and the link. In addition, hardware is available that displays onscreen information as braille. It is imperative that web designers produce web pages that effectively support the use of these tools.
Web accessibility guidelines
A variety of guidelines pertaining to web accessibility have been prepared. Two well-known guidelines are the WCAG 2.0 and the United States government Section 508 Amendment to the Rehabilitation Act.
The Web Content Accessibility Guidelines 2.0 (WCAG 2.0) provides recommendations regarding the accessibility of web content. It was established by the World Wide Web Consortium (W3C) and was written for all web designers, web site creators, and authoring tool developers. Web content developed in conformity with these guidelines does not benefit only impaired persons; regardless of the device used, such as cell phone, PC browser, smartphone, and so on, it provides standards for making information on web pages easy to find for all end users. The Section 508 Amendment to the Rehabilitation Act is a law requiring that all IT devices, software, and web sites procured, developed, or used by United States government agencies must be accessible to those with disabilities. As a result, all companies that deliver products for use by public institutions and the United States government must place some emphasis on web accessibility.
Several methods can be used to identify problems encountered by visually impaired users as they interact with web pages. G. Gay et al. proposed a method to discern accessibility problems that cannot be identified automatically by accessibility checking tools (Greg and Cindy 2010). For example, when a web page contains movie content, this tool recognizes that the page may have accessibility issues. A. Gonzales et al. defined a platform-independent accessibility API framework (Gonzalez and Reid 2005). This method can be used by web designers to identify and address accessibility problems. With the method presented in this paper, visually impaired users can be aware of the content of linked web pages without actually accessing the links. Even if web site accessibility is insufficiently implemented, our approach makes page contents intelligible to users.
Classification of 2 companies web pages links using our method
Company A (11,332)
Company B (14,687)
Link to own page
(Other site) ∗
The “Article” category consists of text. These pages can therefore be read aloud by screen readers, and visually impaired users can understand the content. The web site of Company B contained more than 2 times the number of links of the “File” type compared to Company A. These pages are less accessible to visually impaired users. For example, the contents of movie files that do not contain voice information cannot be understood. Even if sounds and voices are included in a movie file, support for visually impaired users is not enough. When visually impaired users understand movie file contents, movie files should include explanation of the movie with voices. We evaluated a page as having high accessibility if it had few file-type links. The web site of Company B contained more than 10 times the number of pages in the “Plug-in” category compared to Company A. We cannot know whether a plug-in module is accessible to end users with impairments of various kinds, and we therefore evaluated a site as having high accessibility if it had few “Plug-in” category pages.
Our results confirmed the findings of Nikkei, namely that the web site of Company A demonstrated superior accessibility. Our method of classifying a web page’s links is therefore effective as a means of evaluating accessibility.
In this paper, we proposed a method of classifying web pages using link analysis. We classified links into categories, and used these categories to successfully assess web page accessibility.
Future works are as follows:
Finding out category classification
Our survey classified web pages into 8 categories. To more appropriately perform instruction-linked page for end users, we will attempt to determine web page categories.
Developing highly accurate classification
We will consider ways in which details of web page classification, such as HTML tags, contribute to accessibility support.
Supporting style sheet analysis
Expression of links varies when style sheets are used. We will evaluate the importance of links based on the method with which they are expressed.
We thank support of Kanagawa Institute of Technology and Waseda University. We would like to thank anonymous reviewers and assistants.
- Freedom Scientific Inc.: JAWS for Windows. 2011.http://www.freedomscientific.com/products/fs/jaws-product-page.asp Google Scholar
- Greg G, Cindy QL: AChecker: open, interactive, customizable, web accessibility checking. Proceedings of the 2010 International Cross Disciplinary Conference on Web Accessibility (W4A), Article No. 23 2010.Google Scholar
- Gonzalez A, Reid LG: Platform-Independent Accessibility API: accessible document object model. Proceedings of the 2005 International Cross-Disciplinary Workshop @on Web Accessibility (W4A) 2005, 63-71.View ArticleGoogle Scholar
- Nikkei: Company Site Ranking 2009 (in Japanese). 2010.http://www.nikkeibpm.co.jp/chosa/web/sr/index.shtml Nikkei BP.Google Scholar
- Section 508 Homepage: Electronic and Information Technology. 2011.http://www.access-board.gov/508.htm Google Scholar
- Web Content Accessibility Guidelines (WCAG) 2.0: W3C Recommendation 11 December 2008. 2008.http://www.w3.org/TR/WCAG20/ Google Scholar
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.