Technology

Parsing

Ensuring that Web pages have complete start and end tags and are nested according to specification helps ensure that assistive technologies can parse the content accurately and without crashing.

What to check

• Validate all page HTML, and avoid significant validation / parsing errors. Use the W3C’s markup validation service as a starting point.

Degradation

Users may lack the most up to date software or browser to view the website, compromising their experience. A good site should degrade well in case JavaScript and CSS fail to load or are unavailable.

JavaScript is the programming language of HTML and the web; however, some users either do not have JavaScript or choose to disable it for speed or security reasons. If this is the case, ensure that the website can still function and present information without JavaScript running.

CSS is the language that describes the style and presentation of HTML webpages, including colours, layout, and fonts. CSS also allows websites to adapt to different screens. If disabled for any reason, the website should be able to continue to display all of the intended content.

There are accessibility reasons for turning off CSS including users relying on assisted technology who browse the web with custom stylesheets instead.

What to check

Test the website by using the Web Developer Extension for Chrome or Add-on for Firefox:

• JavaScript: under Disable Heading, select Disable JavaScript and reload the page.
• CSS: under CSS heading, select Disable All Style. Note: every time a page is reloaded, CSS has to be disabled.
• Ensure that design elements and content are shown in the correct order with no large gap between content sections.