HTML Accessibility
HTML Accessibility
HTML Accessibility
Always write HTML code with accessibility in mind!
Provide the user a good way to navigate and interact with your site. Make your HTML code as semantic as possible.
Semantic HTML
Semantic HTML means using correct HTML elements for their correct purpose as much as possible. Semantic elements are elements with a meaning; if you need a button, use the <button> element (and not a <div> element).
Semantic
<button>Click Me</button>
Non-semantic
<div>Click Me</div>
Semantic HTML gives context to screen readers, which read the contents of a page out loud.
With the button example in mind:
- buttons have more suitable styling by default
- a screen reader identifies it as a button
- focusable
- clickable
A button is also accessible for people relying on keyboard-only navigation; it can be clickable with both mouse and keys, and it can be tabbed between (using the tab key on the keyboard).
Examples of non-semantic elements: <div> and <span> - Tells nothing about its content.
Examples of semantic elements: <form>, <table>, and <article> - Clearly defines its content.
Headings Are Important
Headings are defined with the <h1> to <h6> tags:
Example
<h1>Heading 1</h1>
<h2>Heading 2</h2>
<h3>Heading 3</h3>
<h4>Heading 4</h4>
<h5>Heading 5</h5>
<h6>Heading 6</h6>
Search engines use the headings to index the structure and content of your web pages.
Users skim your pages by its headings. It is important to use headings to show the document structure and the relationships between different sections.
<h1> headings should be used for main headings, followed by <h2> headings, then the less important <h3>, and so on.
Note: Use HTML headings for headings only. Don't use headings to make text BIG or bold.
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Alternative Text
The alt attribute provides an alternate text for an image, if the user for some reason cannot view it (because of slow connection, an error in the src attribute, or if the user uses a screen reader).
The value of the alt attribute should describe the image:
Example
<img src="img_chania.jpg" alt="Flowers in Chania">
If a browser cannot find an image, it will display the value of the alt attribute:
Example
<img src="wrongname.gif" alt="Flowers in Chania">
Declare the Language
You should always include the lang attribute inside the <html> tag, to declare the language of the Web page. This is meant to assist search engines and browsers.
The following example specifies English as the language:
<!DOCTYPE html>
<html lang="en">
<body>
...
</body>
</html>
Use Clear Language
Always use a clear language, that is easy to understand. Also try to avoid characters that cannot be read clearly by a screen reader. For example:
- Keep sentences as short as possible
- Avoid dashes. Instead of writing 1-3, write 1 to 3
- Avoid abbreviations. Instead of writing Feb, write February
- Avoid slang words
Create Good Link Text
A link text should explain clearly what information the reader will get by clicking on that link.
Examples of good and bad links:
Good
Find out more about the HTML language
Read more about how to eat healthy
Bad
Buy tickets to Mars here
The title Attribute
The title attribute specifies extra information about an element.
The information is most often shown as a tooltip text when the mouse moves over the element.
The title attribute can be used on any HTML element (it will validate on any HTML element. However, it is not necessarily useful).
Example
<p><abbr title="World Health Organization">WHO</abbr> was founded in 1948.</p>
<p title="Free Web tutorials">W3Schools.com</p>