Links and navigation: Links for serial navigation
Web users who are blind often use a screen reader or a Braille display to visit websites. The main difference between this method of visiting a site and using a graphic browser, is that a screen reader or Braille display presents the content step by step, from beginning to end. Navigation through this content is called serial navigation.
Programmes for serial navigation are by now highly capable of guiding the user through the content of the page; the user can often skip through the content from one heading to another (see also Why is descriptive markup important?). Nevertheless, web developers can pay extra attention to groups of visitors who rely on serial navigation.
- Provide the option of skipping over long lists of links.
If the HTML contains a long list of links – for instance, main navigation or subnavigation – provide a link before this list which visitors with visual or mobility impairments can use to skip over this list. These types of links are often called skip links, in view of the possibility of skipping over content.
- Think of a favourable the content order within the source code of the document.
Place the main content of the page as high as possible in the HTML source code.
- On pages with numerous topics, provide a visible index list at the top of the page, with links to jump to the various topics on the page.
This is also useful for visitors who have no a visual impairments. See also Links to page anchors on the use of anchors.
On pages with numerous topics, provide a page index at the top of the page, with links to navigate to the different topics.
Give blind visitors additional options to skip long lists of links.
Links for skipping long lists
With regard to serial navigation, visitors with a mobility impairment who are dependent on navigating websites by means of a keyboard constitute a special group: whereas they usually have an overview of the content of the page, they need to be able to navigate from link to link (see also Tabbing between links). For them, long lists of links can likewise contitute an obstacle.
A link for skipping a section of the page content, for example, a long list, can appear as follows.
The skip link takes the user to a page anchor in the content that follows the list. See also Links to page anchors on the use of anchors.
Correct order: long navigation lists after the main content
Many websites have a long list of navigation links on the left hand side in the page layout. Behind the scenes, in the HTML source code, this list of links often appears before the main content. For people who use screen readers and Braille displays – as well as for search spiders, which also run through web pages serially – this means that they are confronted with a large collection of links before arriving at the main content of the page.
These lists can be skipped if the web developer has added skip links, but sometimes it is more effective to change the order of the content on a page: make sure that the main content of the page appears as high as possible in the HTML source code.
This principle only applies if there is a lot of secondary content before the main content. A short list of navigation links before the main content will not cause many problems and can simply be left in place.
In order of importance
Search spiders use the following logic: important content appears first on the page. According to some web developers, navigation is extremely important – they are right – but it is rarely the most important thing on the page. The reason why a visitor visits the page is for the main content. The navigation needed to get there from another place is less important.
Frequently, visitors arrive at individual pages by way of search engines. In that case, they don’t use the website's navigation.
Rank the content of the page in the HTML source code in order of importance.
The benefits of a correct order of page content
- Search spiders will regard the main content at the top of the web document as very important.
Search results will be more favourable (and therefore more effective) for this page than if no attention has been paid to the order of the page content.
- Visitors using screen readers and Braille displays will have less difficulty accessing the main content of the page.
This principle will also benefit users of older browsers that provide insufficient CSS support. For them too, the main content will appear at the top of the page, even if they lack an attractive visual layout.
Thanks to CSS (Cascading Style Sheets) the various pieces of content can be ranked in the HTML source code in the layout, virtually independent of the order.
Serial accessibility of page content
Providing a (visually hidden) skip link at the top of the document can help visitors with screen readers and Braille displays to skip the main content and access the list of navigation links quickly. A number of other useful links can be added here as well.