The guidelines are broken down by four main principles: perceivable, operable, understandable, and robust. Under each principle, there are guidelines that provide specific goals a website should work toward. Under each guideline, there are testable success criteria. Those criteria are graded A, AA, or AAA. This grade shows the level of conformity to accessibility, AAA being the highest. The law only requires A and AA guidelines to be met.
Vu said that she gets one question all the time: What are the legal standards? There is no legal standard, but there are guidelines out there: The Web Content Accessibility Guidelines (WCAG), version 2.0, with 3 levels of conformity: A, AA, AAA. They were put out by W3C. Companies can use those guidelines. The Justice Dept. uses the A and AA levels.
Finally, WA11Y is another top ADA compliance plug-in to consider. A toolbox of resources to help you meet most ADA compliance needs, the plug-in packs multiple accessibility tools, each with a unique purpose. Tota11y, the first tool in the box, for instance, annotates all elements of your web pages and identifies any accessibility issues. Another tool in the box, WAVE, performs a detailed accessibility analysis of each page and provides printable reports. Then, you have FILTERS which is used to modify data within Wa11y.

If you do get sued, if you immediately remediate your website, you may be able to get the lawsuit dismissed on mootness (there’s no longer anything in dispute, i.e. plaintiffs are arguing your website is inaccessible but you’ve already made it accessible). This definitely does not mean you should wait to fix your website but it does mean you may have an out.
Error prevention on important forms (3.3.4): For pages that create legal commitments or financial transactions or any other important data submissions, one of the following is true: 1) submissions are reversible, 2) the user has an opportunity to correct errors, and 3) confirmation is available that allows an opportunity to review and correct before submission.

Luckily, the international nonprofit World Wide Web Consortium (W3C) brings together smart people who develop open standards to ensure the long-term growth of the Web. They produce recommendations for making websites fair and equally accessible for the highest number of people possible. Their Web Content Accessibility Guidelines (WCAG) 2.1 offer clear guidance for web developers to achieve ADA compliance.
Accessibility on the web can mean a lot of things. But in general it means making websites as inclusive to as many users as possible. Accessibility is important for a diverse group of users including mobile users, people who rely on assistive technology to navigate the web, and even search engine robots. We handle accessibility of in two simple ways.
Navigable: Content that’s repeated on multiple pages can be easily skipped. All pages have informative titles, headings, and labels that describe the page’s content and hierarchy. Navigating the page must take place sequentially, in a meaningful order that preserves relationships on the page. All link text is descriptive in order to make clear where the link will take users. If users are navigating via a keyboard, the current focus of the keyboard is always highlighted and visible.
When choosing an aid or service, title II entities are required to give primary consideration to the choice of aid or service requested by the person who has a communication disability. The state or local government must honor the person’s choice, unless it can demonstrate that another equally effective means of communication is available, or that the use of the means chosen would result in a fundamental alteration or in an undue burden (see limitations below). If the choice expressed by the person with a disability would result in an undue burden or a fundamental alteration, the public entity still has an obligation to provide an alternative aid or service that provides effective communication if one is available.
The Federal Communications Commission (FCC) enforces regulations covering telecommunication services. Title IV of the ADA covers telephone and television access for people with hearing and speech disabilities. It requires telephone and Internet companies to provide a nationwide system of telecommunications relay services that allow people with hearing and speech disabilities to communicate over the telephone.