HyperText Markup Language

The acronym HTML stands for HyperText Markup Language and refers to the core language of the World Wide Web (W3C 2018). In 1989, when Tim Berners-Lee invented the Web, he used HTML as its publishing language with the idea of gathering information from researchers all around the world and link all their studies to each other, to obtain cross-references from one research to another. In simpler words, HTML is the text format of websites (Raggett et al.

1998). In its first ten years, until 1998, this markup language kept developing, resulting in the HTML 4.0 version. As people in the industry started focusing on different types of languages to provide web content, HTML was put aside. However, as new technologies such as XForms were introduced, the industry started working on a new version, introduced in 2014: HTML 5.0 (W3C 2018). The latest version, HTML 5.3, was published on the 18^th October 2018³.

HTML5 is based on four design principles: compatibility, utility, interoperability, and universal design. The latter concerns directly our research, as it includes accessibility among its three concepts (the other two being media independence and support for all world languages).

According to this concept, design features should be accessible to everyone regardless of their abilities, particularly to people with disabilities (Lawson & Sharp 2010, 3-5; Lubbers, Albers

& Salim 2010, xiii; W3C 2007).

Moreover, HTML5 specifications include what has previously been specified in HTML 4.1, XHTML⁴ 1.1 and DOM⁵ Level 2 HTML (W3C, 2018) and “it has moved HTML from being a relatively simple document markup language to being a sophisticated platform for web applications with a host of new, rich application programming interfaces (APIs)” (O Connor 2012, 1). Therefore, new features and new elements (see Appendix A) were introduced in this

3 https://www.w3.org/TR/html53/introduction.html#introduction [15.6.2019]

4 Extensible HyperText Markup Language: an almost identical but stricter HTML defined as an XML (eXtensible Markup Language) application.

5 Document Object Model: it defines HTML elements as objects and their properties, methods, and events. It is also an API for JavaScript.

latest version, which often presents many challenges to users, and especially to people with disabilities (ibid.).

This new version has a host of elements that include a broad range of new functions. First, developers introduced new semantics: elements, attributes, and attribute values have specific meanings and they are used only for their intended purpose (O Connor 2012, 128; W3C 2018a).

Thus, new semantic markup is used to describe the element’s content (Lubbers et al. 2010, 10).

In the context of our research, we deem it important to emphasise that semantic information is essential to ensure accessibility, as assistive technologies use it to provide information to present the document and to provide additional functionalities (W3C 2018a).

We can use semantic information to structure the document. HTML5 provides many new sectioning elements, such as <header> (which includes the header’s content, at the top of the page) and <section> (which include a section’s content in the document’s body), as we illustrated in Figure 2.1.

Figure 2.1: Basic structure of an HTML document (adapted from O Connor 2012, 167; Lubbers et al. 2010, 11-12).

Second, every element includes information about the category it belongs to, the context it is used in, the ‘content model’ that defines the element’s content, and the DOM interface implemented (O Connor 2012, 142-3). Concerning the category the element belongs to, we can find different types of content; however, one element can have different characteristics, and for this reason, it can fall under several categories. As illustrated in Table 2.1, content can be divided into the following categories: metadata, flow, sectioning, heading, phrasing, embedded, and interactive (Lubbers et al. 2010, 10; O Connor 2012, 143-52; W3C 2018a).

Content model Description

Metadata content This kind of content outlines the presentation of the page, the behaviour of the content, and the relationships with other documents (W3C 2018a).

Flow content It includes all the main elements used in the body of a document (ibid.).

Sectioning content It defines new sections that can be grouped together and defines the scope of a certain part of the document, such as headings and footers (O Connor 2012, 147; W3C 2018a).

Heading content This kind of content helps determine the structure of the page and defines the header of a section (O Connor 2012, 147; W3C 2018a).

Phrasing content “This is the main body of text in a document and the inline elements used to mark up the content” (O Connor 2012, 147). In the context of content models, the term ‘text’ defines nothing or text nodes, which consist of Unicode characters⁶ (W3C 2018a).

Embedded content This kind of content allows the import of another source in the HTML document (O Connor 2012, 150).

Interactive content It defines the “content that is specifically intended for user interaction” (W3C 2018a).

Table 2.1: Content model categories.

Last, among all the new HTML5’s elements, we should talk about one crucial aspect in the context of accessibility and our research: WAI-ARIA. WAI-ARIA (Accessible Rich Internet Applications) is a “technical specification that provides a framework to improve the accessibility and interoperability of web content and applications” (W3C/WAI 2017b). This specification is essential to ensure accessibility, as it allows to include more information than the current HTML5 specification can provide (O Connor 2012, 135). An ARIA element is usually added to the native HTML element (ibid., 140) and, except cases where there are restrictions, web developers can use the ARIA role or aria-* attributes (W3C 2018a). For instance, when an HTML element is followed by the attribute hidden, the author can

6 The Unicode Standard ist he universal character encoding standard for written characters and text:

https://www.unicode.org/versions/Unicode12.0.0/ch01.pdf [17.6.2019]

introduce the ARIA semantics ‘aria-hidden’ and set it to ‘true’ (O Connor 2012, 139). In this way, a screen reader will ignore the element and avoid to read it to the user.

2.2 Web accessibility

As we have seen in Chapter 1, web accessibility consists of developing websites and technologies that are designed for everyone, in particular people with disabilities. In the following section, we briefly examine the WCAG guidelines, as they provide the basis for the selection of the research material and the selection of a set of requirements.