HTML and CSS Reference
A search function is vital for all web sites because it might help users find content. A popular approach for
providing a search function to web sites is to create a site-specific Google search field (also shown in the previous
example). The Search button should be adjacent to the search field.
Content sections must begin with a heading element to provide structure ( h1 - h6 ). Descriptive headings and
labels must be provided that allow users to select the information relevant to them. Pages can be organized efficiently
with headings. In (X)HTML5, document introductions should apply the header element.
The order of content in the source code must coincide with the default visual presentation of the content; in other
words, the DOM order must match the visual order. Dynamic content inserted into the Document Object Model
right after the element used to activate the dynamic content insertion ensures a correct tab order (and thus a correct
reading order for screen readers) through the exploitation of the default tab order of user agents. Web page content
must be ordered in a meaningful sequence. This also holds for interactive elements. Page section reordering must
be performed by using the DOM. Repeated components should always be presented in the same order. Users must
be allowed to skip repeated menu items through expandable and collapsible menus. Flash contents must apply the
tabIndex property in order to specify a logical reading order and a logical tab order.
A site map and a table of contents also contribute to accessibility. A help link may be added to every web page. A
dedicated help page can be used to collect information that can be helpful for less experienced users but omitted
from the main content, because they are evident (and even disturbing) for most users. Moreover, a help page might
provide information about special web site features that are not common on the Web. For example, a user of a
highly accessible web site can be informed about the option to control the menu with keyboard buttons, which is
not available on every site. Help may also be provided in the form of an assistant who gives a tour to new visitors on
the functionality and content of the site. Such an assistant can be presented as an animation with a digital character
(also known as a multimedia avatar) or a video clip with a real person, who gives instructions or a service overview or
explains concepts related to the company portfolio (Figure 10-3 ).
Figure 10-3. An assistant (video clip with a real person)