# Evaluating Progressive Web App Accessibility for People with Disabilities
## 4 Web Accessibility
### Guidelines and Regulations
They improved the structure and consistency of the prior guidelines and, at the same time, added additional success criteria. The checkpoints were renamed to success criteria and the priority was assimilated from Level A to AAA. WCAG 2.0 is organized around four design principles that provide the foundation for web accessibility (perceivable, operable, understandable, and robust) [20]. * [noitemsep,topsep=0 pt]
* Level A is the minimum level that defines the foundations of web accessibility [30]. It consists of 12 guidelines, including 25 success criteria. * Level AA includes all Level A and AA requirements [23]. In addition, it attaches 13 new success criteria to the existing six guidelines. These success criteria provide the basic objectives that authors must achieve to create more accessible content for users with different levels of disability [30]. * Level AAA includes all Level A, AA, and AAA requirements [23]. Moreover, it attaches 23 new success criteria to the existing nine guidelines. These success criteria allow for the evaluation of requirements and needs, such as design specifications, purchasing, regulation, or contractual agreements [30]. WCAG's 2.1 updated version came in June 2018. WCAG 2.1 came as an extension of the 2.0 version, adding five A, seven AA, and five AAA success criteria to the existing guidelines. The newest WCAG 2.2 was introduced as a working draft in August 2020 and updated in May 2021. WCAG 2.2 extends its predecessor's guidelines, adding the following nine success criteria [31]:  
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* Accessible Authentication (3.3.7; Level A). * If an authentication process relies on a cognitive function test, then at least one other method must also be available that does not rely on a cognitive function test [31]. Cognitive deficits usually occur in older people [32], who find it difficult to memorize passwords, make calculations, or even solve a puzzle. Since this success criterion is required for conformance to Level A, there must be an alternative method in case the website uses a cognitive authentication function. * Redundant Entry (3.3.8; Level A). * Redundant entry is a success criterion of Level A, which requires auto-populated or user-selected information in fields previously entered by the user. However, there is an exception when re-entering essential information [31]. * Consistent Help (3.2.6; Level A). * When facing problems completing a task on a website, people with some types of disabilities may not be able to work through the issue without further help. Issues could include difficulty completing a form or finding a document or page that providesthe information required to complete a task [31]. Therefore, up-to-date Frequently Asked Questions and human contact details, or a messaging mechanism is required. * Page Break Navigation (2.4.13; Level A). * The purpose of this success criterion is to allow people using assistive technology or screen readers to find references to content based on the page break locators found in the default view or printed version of a publication [31]. * Dragging Movements (2.5.7; Level AA). * All functionality that uses a dragging movement for operation can be operated by a single pointer without dragging, unless dragging is essential [31]. Dragging movements are observed in services such as Google Maps on mobile phones, where more pointers are needed to drag a map. * Target Size (2.5.8; Minimum; Level AA). * This success criterion belongs to the AA conformance level and aims to help users with hand tremors and those who have difficulty with fine motor movement to activate interactive areas, such as in-line links and pop-over content accurately. Visible Controls (3.2.7; Level AA). * The controls needed to progress or complete a process are visible at the time they are needed without requiring pointer hover or keyboard focus, or a mechanism is available to make them persistently visible [31].