This specification is limited to providing a semantic-level markup language and associated semantic-level scripting APIs for authoring accessible pages on the web ranging from static documents to dynamic applications.
This means that this document only defines the rules and standards for creating web pages and web applications that have meaningful and understandable content and structure, as well as ways to interact with them using scripts. Scripts are pieces of code that can add functionality and behavior to web pages and web applications. Semantic-level means that the language and the scripts focus on the meaning and purpose of the content and structure, rather than the appearance or presentation.
The scope of this specification does not include providing mechanisms for media-specific customization of presentation (although default rendering rules for web browsers are included at the end of this specification, and several mechanisms for hooking into CSS are provided as part of the language).
This means that this document does not define how web pages and web applications should look or sound on different devices or media, such as screens, printers, speakers, etc. Presentation is the aspect of web development that deals with the appearance and style of web pages and web applications. However, this document does provide some basic rules for how web browsers should display web pages and web applications by default, as well as some ways to connect HTML5 with CSS. CSS is a language that can style and format the presentation of web pages and web applications.
The scope of this specification is not to describe an entire operating system. In particular, hardware configuration software, image manipulation tools, and applications that users would be expected to use with high-end workstations on a daily basis are out of scope. In terms of applications, this specification is targeted specifically at applications that would be expected to be used by users on an occasional basis, or regularly but from disparate locations, with low CPU requirements. Examples of such applications include online purchasing systems, searching systems, games (especially multiplayer online games), public telephone books or address books, communications software (email clients, instant messaging clients, discussion software), document editing software, etc.
This means that this document does not define how a computer system should work or function, or how to control or modify its hardware components. Hardware configuration software and image manipulation tools are examples of software that deal with these aspects. This document also does not define how to create or use software that requires a lot of computing power or resources, or that are used frequently by professionals or experts. High-end workstations are examples of computers that have these capabilities. Instead, this document defines how to create or use software that can be accessed and used easily and conveniently by anyone from anywhere on the web, using any device that has a web browser. These software have low CPU requirements, which means they do not need a lot of computing power or resources to run. The examples given are some of the common types of software that fall under this category.
