Understanding WCAG 2.0: 2.4.3 – Focus Order

The next standard we’ll explore in our series on understanding WCAG 2.0 is 2.4.3, Focus Order. This standard is required for WCAG level A compliance, which is part of what Section 508 requires. Here’s the complete text:

2.4.3 Focus Order: If a Web page can be navigated sequentially and the navigation sequences affect meaning or operation, focusable components receive focus in an order that preserves meaning and operability. (Level A)

Any part of a program or web page that can receive input from the user can have focus. Let’s take a look at a webform, so we have a something to reference:

This is an interactive webform, so you can click in either of the input boxes. Go ahead, try it right now. I’ll wait.

There’s four elements on that page that could receive focus, but only three that can. I’ve marked the submit button as disabled, so you can’t click it. That element can’t have focus, so you can’t submit the form.

There’s a couple ways to navigate that form. If you’re sighted, you might use the mouse to first click in the first box, and then again to click in the second box. But if you can’t see the screen, it’s hard to use a mouse. Instead, you’d probably use the tab key to move between elements.

The sequence focus follows when tabbing is called the tab order, and is set using the tabindex attribute on html elements. I didn’t set the tab index on any of those elements, so the browser automatically fills in the tab order for us, using the structure of the HTML – in this case, from top to bottom. But take a look at this form:

Doesn’t that feel a little… evil?

For the purposes of editing our web pages, that’s really all there is to this standard. Make sure that the order you move from input to input on your pages makes sense. And if it doesn’t, use the tabindex attribute to fix it.

If you’re doing web development, there’s a little more to consider. Using CSS, it’s possible to position elements in a different order visually than the way they’re written in code. That isn’t necessarily against the rules, but you need to make sure the tab order still works (in addition to the concerns in 1.3.2). Also be alert to things like modal dialogs, or popovers which can visually steal focus from the webpage, but which may not trap the tab key, and may mean someone with low vision can only see the modal, but can still tab outside of it.

If you’d like to read more about focus order, you may also be interested in these techniques, which provides examples and more detail.

And if you’ve never watched a blind person use a computer, you really should. That video is part of a great, funny collection of videos on what it’s like to live without sight.

Interested in more? Check out the listing of all the posts in this series.