1. Introduction

In this tutorial, our main goal is to learn how to test and validate keyboard navigation on a website. Keyboard navigation refers to the ability to navigate a website using only the keyboard, which is crucial for accessibility.

By the end of this tutorial, you'll know:
- How to test your website's functionality with keyboard-only navigation
- How to identify issues in keyboard navigation and focus management
- How to validate your website's keyboard navigation

There are no prerequisites for this tutorial, but familiarity with HTML, CSS, and JavaScript will be helpful.

2. Step-by-Step Guide

Keyboard navigation testing involves using the Tab, Shift+Tab, arrow keys, Enter, and Space keys to navigate through the interactive elements of your website, such as links, buttons, form fields, etc.

Testing Keyboard Navigation

1. Start at the top: Begin at the top of your webpage. Use the Tab key to navigate forward through interactive elements and Shift+Tab to navigate backward.

2. Check for visible focus: As you tab through elements, ensure that each element has a visible focus indicator. This is usually a border or a highlight.

3. Check order: The tabbing order should be logical and intuitive, generally following the visual flow of the page.

4. Check all elements: Make sure all interactive elements are reachable and usable with the keyboard.

Validating Keyboard Navigation

After testing, it's time to validate your findings. This involves:

1. Identify issues: Document any issues you found during testing. This could be missing focus indicators, elements that can't be reached with the keyboard, or a confusing tab order.

2. Fix issues: Use HTML, CSS, and JavaScript to fix the issues. This might involve adding tabindex attributes, improving CSS for focus indicators, or adding JavaScript for more complex interactions.

3. Retest: After making changes, retest keyboard navigation to ensure the issues have been fixed.

3. Code Examples

Let's look at some examples of common issues and how to fix them.

Example 1: Adding a Visible Focus Indicator

<!-- Before -->
<button>Click me!</button>

<!-- After -->
<button style="outline: 2px solid blue;">Click me!</button>

In this example, we've added a blue outline to the button when it's focused. This makes it clear to keyboard users which element is currently focused.

Example 2: Fixing Tab Order with tabindex

<!-- Before -->
<div>First element</div>
<button>Second element</button>

<!-- After -->
<div tabindex="0">First element</div>
<button tabindex="1">Second element</button>

In this example, we've used the tabindex attribute to specify the tab order. The div will now be focused before the button.

4. Summary

In this tutorial, we've covered how to test and validate keyboard navigation. We learned how to navigate a website using only the keyboard, identify issues with focus indicators and tab order, and fix these issues using HTML, CSS, and JavaScript.

For further learning, consider reading more about accessibility best practices and exploring more complex keyboard interactions like keyboard shortcuts and ARIA roles.

5. Practice Exercises

1. Exercise 1: Go to a popular website and test its keyboard navigation. Document any issues you find.

2. Exercise 2: Build a simple webpage with a few interactive elements. Test and validate its keyboard navigation.

3. Exercise 3: Add more complex interactions to your webpage, like a dropdown menu or modal. Test and validate its keyboard navigation.

Remember, the key to improving your skills is practice and experimentation. Happy coding!