Accessibility Guide

A curated collection of web accessibility tips, tricks and best practices

Table of Contents

Tips

Pro Tips

Facts

Tips

Always include alt attribute on an image

Screen readers for the blind and visually impaired read out alt attribute text and therefore make your images accessible. alt attribute should describe meaningful images and be left empty if the image serves decorative purposes. Never leave the alt since screen readers will read the source of the image which makes for terrible user experience.

Resources

• Some things about alt text

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Avoid auto-playing audio on your website

Do not auto-play any audio or video material on page load. Users with screen readers will hear both 3rd party audio and their screen reader which makes for a poor user experience.

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Buttons that only show up on hover

Be mindful of a pattern where buttons are hidden and only get displayed when parent element is hovered: this can make the buttons inaccessible from keyboard. instead us using display:none or visibility: hidden, consider using alternative methods, e.g. using position: absolute and pushing it off the screen.

Resources

• See how angular hides elements with cdk-visually-hidden class

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Always feature optimal contrast

Whenever possible make your websites accessible to the eye by avoiding poor contrast between text and background.

Resources

• Accessible color picker
• Accessible color compliance checker
• Color contrast docs by MDN

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Don't remove :focus on elements

If an element is interactive never remove the highlight by setting outline: none; on a focused state of that element. If the default browser outline doesn't align with the design be sure to replace it with a custom accessible one instead of hiding it completely. Removing an element's highlight on focus makes filling out forms difficult for some users.

Resources

• Focusing on Focus Styles

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Use labels on form fields

Once implemented properly, label elements make the form accessible. Each label element should have a for attribute that has the value of the corresponding filed's id.

Resources

• The label element docs

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Make self-validating forms accessible

If your form needs to meet specific input criteria and errors on mistaken input be sure to provide feedback to the user. Alongside the common red border include a text-based informative explanation of the encountered error.

Resources

• Sensible Forms: A Form Usability Checklist

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Follow heading hierarchy

Screen reader users navigate pages by using the heading structure. Do not use headings by picking the one that fits the appropriate size in design. Instead, use heading elements h1 to h6 with the hierarchy in mind and style them later.

Resources

• Headings

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Avoid non-semantic patterns

Use semantic HTML elements that clearly define their content as much as possible. By using semantic elements you provide the user with a more meaningful way to navigate and interact with your website. Semantic elements, such as <header>, <main> and <article> are by default accessible compared to non-semantic elements like <div> or <span>. Avoid using non-accessible <div class="button"> when <button> is already available to you. If for some reason you must use non-semantic elements be sure to implement accessibility functionality to them.

Resources

• Semantics in HTML
• The practical value of semantic HTML

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Use skip-links

Let users skip long navigation by implementing invisible focusable links that leads to the main content. Screen readers perceive the page from top to bottom which means that if there is no skip-link implemented and the website is already familiar to the end user, the screen reader will read redundant navigation.

Resources

• Codepen example

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Make tab friendly navigation

Allow users to use keyboard-only navigation on your website by ensuring that all interactive elements are focusable and in a logical order.

Resources

• Keyboard navigation explained in detail

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When you need to display tabular data use table instead series of div elements

When you need to display some tabular data be sure to use the semantically correct <table> element as it is accessible by default, in contrast to non-semantic elements like <div>. You should provide a <caption> for your <table> element and allow users to skip through the table with a skip-link if they don't want it read by the screen reader.

Resources

• Semantic table docs

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Pro Tips

Alert user for updates

Make on the fly content changes accessible by making use of WAI-ARIA attributes on those elements. When notifying the user about a certain behavior use aria-live attribute to let the screen reader know about new changes. Set the value of aria-live to polite if your changes aren't urgent or use aria-live="assertive" if you want to notify the user immediately.

Resources

• ARIA Live Regions

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Put a full stop at the end of the alt attribute

Put a full stop at the end of an image's description inside the alt attribute, so that screen readers can make a short pause which leads to better user experience.

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Allow user to stop an animation

Complex or even simple animations can make it hard for some users to focus on the actual content of the webpage. Therefore your website should allow users to stop animations on the webpage at a particular keyframe.

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Avoid alt tags on images of your logo

Hearing screen readers pronounce the description of your logo over and over gets tiresome. Use a descriptive alt tag just on the first image of your logo. Remember to include an empty alt tag on others since screen readers will read the image source as the fallback.

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Tables should always include scoping in their HTML

Although scope attributes aren't mandatory in table elements it's is highly recommended to use the scope to indicate what type of data each column contains and what should be read out as a row.

Resources

• HTML table advanced features and accessibility

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Avoid poor video captions

Videos on your websites should have proper captioning. When transcribing video content, it is considered a good practice to avoid vocal pauses and verbal missteps.

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Facts

HTML should have a logical flow

Some screen readers can not figure out the styled layout, so they work with the plain HTML document to figure out in which order they should read the page. Although many screen readers support styled layouts, the safest method is to structure your HTML in a logical flow, so the content is understandable without the need for styles.

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Don't rely just on Lighthouse when testing

Testing your websites for accessibility with off the shelf solutions like Lighthouse isn't enough. Instead, manually test your websites. There are great extensions to help you simulate common user conditions.

Resources

• The Importance Of Manual Accessibility Testing
• Accessibility Testing Tools

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Improve typography on your website

Enhance accessibility and user experience by making your content more comfortable to read. Text on the webpage should be justified to the left with a font-size of 16px at a minimum. line-height of 1.5 is optional to make for a pleasant reading experience.

Resources

• Resource title

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