Links and Hypertext
Introduction to Links and Hypertext

Overview

Hypertext links are one of the most basic elements of HTML, as its name implies (HTML stands for HyperText Markup Language). As such, making hypertext links accessible is one of the most basic and most important aspects of web accessibility. For the most part, this is an easy task. Standard hypertext links work with all technologies and platforms and users of all abilities can access them, whether directly or through the use of some sort of assistive technology. As might be expected though, there is more to hypertext link accessibility than simply creating a link. Some types of links are more accessible than others, and some types of links are completely inaccessible to people with certain types of disabilities. Because links are so basic to the functionality of web content, inaccessible links are one of the most severe barriers to overall accessibility.

Keyboard Accessibility of Links

Users must be able to navigate to and select each link using the keyboard alone. In most browsers, the Tab key allows users to jump from link to link, and the Enter key allows users to select a link. If the only way to access a link is with a mouse, the link is unusable by people who cannot use a mouse. How is it even possible to create a link that is inaccessible by keyboard? The most common method is by using JavaScript event handlers that do not permit keyboard access (see the article on JavaScript Event Handlers). Other ways to render links inaccessible to keyboard users include inappropriately using non-HTML technologies, such as Java or Flash to create links within an HTML document. Both Java and Flash can be made accessible, but only if the developer designs with accessibility in mind. Overall, creating accessible HTML links is easier and more straightforward than creating accessible links in other technologies.

One of the most serious barriers is to create links that go nowhere. Developers sometimes use JavaScript to create dynamic menus that drop down when the user hovers over certain links with the mouse. In some cases, the link itself goes nowhere at all, and its only purpose is to expose the links in the drop-down menu, which do have real destinations. Links like this often have a pound sign as the link destination, which means that the link destination is the same page; clicking on the link accomplishes nothing. Both keyboard users and mouse users will experience nothing at all when attempting to activate the link.

Mouse users will at least be able to click on the links in the drop-down menu, but keyboard users cannot access the drop-down menu, so the link is completely useless and all of the link destinations in the drop-down menu are completely inaccessible to them. One solution is to abandon the drop-down menu and instead use standard hypertext links. Another solution is to specify a real link destination (e.g. href="products.htm") which would list the same links that are available via the drop-down menu. For more information see example 2 in onMouseOver section of the JavaScript Event Handlers article.

Screen Readers and Links

People who use screen readers to access the web most often use their keyboard rather than their mouse, so keyboard accessibility is an important first step in making hypertext links accessible to screen reader users. Beyond basic keyboard accessibility, it helps to know how screen reader users access links.