Web accessibility 101: a quick intro and the Key Principles

Sergey Lebedev
4 min readJul 28, 2023


Welcome to the world of web accessibility, where we strive to create an inclusive online environment for all users. In this article, we will embark on a journey to understand the key principles that form the foundation of web accessibility. By the end of this guide, you’ll have a solid grasp of the principles and practical techniques to make your web content more accessible. So, let’s get started!

Understanding the Key Principles

At the heart of web accessibility lies four fundamental principles defined by the Web Content Accessibility Guidelines (WCAG): Perceivable, Operable, Understandable, and Robust. Let’s take a closer look at each of these principles and understand their significance in creating an inclusive web experience.

Perceivable: Making Content Sensible to All Senses

The perceivable principle is all about making sure that information and user interface components are presented in a way that users can perceive them through their senses. This principle is crucial for users with visual or hearing impairments, as well as those who may have difficulty processing certain types of content. Here are some key aspects of perceivability:

Semantic markup

Semantic markup is the cornerstone of perceivability. By using appropriate HTML tags and ARIA (Accessible Rich Internet Applications) attributes, we enable screen readers and other assistive technologies to interpret web content correctly. Proper semantic markup ensures that content is understood on a more general level, providing a better user experience for everyone. For instance, using <h1> to <h6> tags for headings and associating form elements with their labels through for and id attributes.

Operable: Navigating with ease

Operability focuses on making web content and navigation easily operable by a wide range of users. This principle is vital for users with motor disabilities who may rely on keyboards or other input devices. Key elements of operability include:

Keyboard accessibility

Keyboard accessibility is at the heart of operability. It ensures that users who cannot use a mouse can still navigate and interact with the website effectively. Every interactive element, from buttons to form controls, should be accessible via the tab key. Additionally, all modals and popups should be accessible, and focus should be appropriately managed within these elements.

Focus management

Providing clear and visible focus indicators helps users navigate through interactive elements and understand where they are on the page. Proper focus management is especially crucial for users who rely on keyboard navigation.

Skip links

Implementing skip links allows users to bypass repetitive content and jump directly to the main content of the page, enhancing efficiency and ease of navigation.

Understandable: Clarity and comprehensibility

To deliver an exceptional user experience, we must make web content understandable to everyone. The understandable principle aims to create content that is clear and easy to comprehend for all users, including those with cognitive disabilities. Key considerations for understandability are:

Visual assistance

Visual assistance plays a crucial role in improving the understandability of web content. By adhering to color contrast guidelines (at least 4.5:1), providing visual focus indicators, and creating responsive designs that retain functionality at 200% zoom, we enhance the overall user experience.

Language and reading level

Using plain language and avoiding jargon helps users better understand the content. Clear and concise writing enhances the overall user experience.

Error handling

Providing clear and concise error messages with suggestions for correction helps users correct mistakes and proceed smoothly. Well-designed error messages reduce frustration and confusion for all users.

Robust: Future-proofing your accessibility

Robustness ensures that web content is compatible with a variety of browsers, devices, and assistive technologies. This principle is essential for future-proofing your website and making it accessible for all users, regardless of the technologies they use. Key aspects of robustness include:

Cross-browser compatibility

Testing your website on various web browsers and ensuring it functions correctly on each one ensures a consistent experience for all users.

Responsive design

Implementing responsive design principles allows your website to adapt to different screen sizes and devices, making it more accessible to users on mobile devices and tablets.

Compatibility with assistive technologies

Ensuring that your website works seamlessly with screen readers, braille displays, and other assistive technologies empowers users with disabilities to access your content effectively.

As we journey through the principles of web accessibility, we uncover the underlying philosophy of inclusive design — building a web that leaves no user behind. By embracing semantic markup, keyboard accessibility, and visual assistance, we create an environment where all users can perceive, interact, and understand content effortlessly. The journey doesn’t end here; in fact, it’s just the beginning. In the next articles, we’ll explore a11y design patterns, validation checklists, and advanced tools to solidify our knowledge and craft accessible digital experiences that empower and delight all users. So let’s embark on this adventure together, championing the cause of web accessibility every step of the way!

Don’t miss out on the opportunity to enhance your web development skills and foster inclusivity in your designs. Join us in the next article as we dive into the world of A11y design patterns and validation techniques. Let’s build a web that is welcoming and accessible to all!

Additional Resources

  1. Web Accessibility Initiative WAI: Strategies, standards, and supporting resources for making the Web more accessible.
  2. WAI-ARIA: Specification defining additional HTML attributes to improve accessibility.
  3. ARIA Authoring Practices Guide (APG): Approaches to make widgets, navigation, and behaviors accessible.
  4. WebAIM: Tutorials, tools, and evaluations for web accessibility.



Sergey Lebedev

Senior Frontend Developer • Team Lead • JavaScript, Angular, React, TypeScript • UI/UX