Use CSS HTML Validator Home, Pro or Enterprise to help check for:
More detailed information about what is checked can be found in these documentation pages:
CSS HTML Validator Home, Pro or Enterprise Software for Windows (formerly CSE HTML Validator) is a powerful tool that can be used to check web documents for issues that affect accessibility, usability, and functionality. Checks are based on WCAG 1.0, WCAG 2.0/2.1, and/or Section 508 requirements.
NOTE: Be sure to turn accessibility checking on in the Accessibility section of the Validator Engine Options (go to). Read below for more information about accessibility and how CSS HTML Validator can help.
Did you know? Compliance with WCAG 2.0/2.1 (at Level AA) has become the de facto baseline for government regulators, courts, advocacy groups, and private plaintiffs for determining whether a website is accessible. CSS HTML Validator can help you with compliance.
Section 508: For US government websites, CSS HTML Validator helps check for Section 508 compliance and has been purchased by many United States government organizations including the Social Security Administration, Federal Highway Administration, Centers for Disease Control, US Postal Service, Department of Agriculture, Department of Commerce, Department of Energy, Library of Congress, FDIC, NASA, NOAA, US Geological Survey, and the US Census Bureau.
Simply open your document (a CSS file or HTML file containing CSS) in the program, press F6, and your document is checked. It's that simple!
Latest version: 20.04
TIP: Don't settle for an accessibility testing tool that doesn't also check the HTML, XHTML, and CSS syntax of the page. An important characteristic of an accessible page is that it is free of syntax problems. CSS HTML Validator checks HTML, XHTML and CSS syntax in addition to checking for other accessibility issues.
When a website is accessible, it means that anyone, regardless of ability, can enjoy and use the website effectively. As an added bonus, it also makes the website more machine readable, and that often has search engine benefits. When a website is not accessible, then people with disabilities can be prevented from having similar access to a web page's information and function compared to someone without a disability. This can result in user complaints and even in lawsuits if the website is legally required to be accessible.
As an example, imagine a website with many images on it (using the img element). A blind visitor may be using a screen reader or talking browser to "view" this page. One of the most significant (and very easy to do) actions a web developer can do to increase accessibility and make a web page more accessible is to supply appropriate alternative text for each image using the alt attribute. This "alt" text is what the user's screen reader or talking browser will read to the blind user because he or she cannot see the images. If this "alt" text is not there, then the web page often becomes inaccessible to blind users.
As an example, consider an image on a product page that says "Buy Now" but there is no alternative text for this image. Because there is no "alt" text, a blind user could easily get lost if they are trying to order the product. Instead, the image should have an alt attribute that is simply alt="Buy Now". This will let a screen reader or talking browser tell the blind user that the image is the order button, and the user will then know what to do to continue ordering the product. Without this simple addition, a blind user would not be able to use the web page as effectively as a user who is not disabled.
There are many reasons why you should make your website accessible:
CSS HTML Validator generates many messages to help you make your website more accessible. Furthermore, unlike other accessibility tools, CSS HTML Validator also generates messages about the syntax problems in your HTML, XHTML, and CSS documents. These syntax problems are often another source of website problems. By utilizing CSS HTML Validator's syntax and accessibility messages, as well as user feedback and human site testing, you'll be well on your way toward having a quality, accessible website.
Please note that although CSS HTML Validator is an indispensable tool for producing accessible and usable websites, no computer program can find all accessibility and usability issues. Therefore, we highly recommends that you utilize human testing and feedback to find any problems that a computer program cannot find. Ensuring accessibility requires a significant amount of manual work. CSS HTML Validator helps reduce the amount of manual work to a minimum by quickly checking your documents and finding certain problems before your website is manually tested.
Download a free trial of CSS HTML Validator Professional to check accessibility, including compliance with WCAG and Section 508 government standards.