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tags: HTML4 SPEC
---

# Section 1: About the HTML 4 Specification

[link](https://www.w3.org/TR/html401/about.html)

## Table of contents
- [How the specification is organized](#How-the-specification-is-organized)
- [Document conventions](#Document-conventions)

## How the specification is organized
- **Sections 2 and 3**: introduction to HTML 4
- introduction to HTML
- history of HTML
- capability of HTML 4
- brief [SGML tutorial](https://www.w3.org/TR/WD-html40-970708/intro/sgmltut.html)
*The Standard Generalized Markup Language, SGML, is a language for defining markup languages. HTML is one such "application" of SGML.*

- **Sections 4 - 24**: HTML 4 reference manual
- What characters may appear in an HTML document.
*SGML requires that each application (including HTML) specify its document character set. A document character set consists of:*
- *A [Repertoire](https://dictionary.cambridge.org/zht/%E8%A9%9E%E5%85%B8/%E8%8B%B1%E8%AA%9E/repertoire): A set of abstract characters,, such as the Latin letter "A", the Cyrillic letter "I", the Chinese character meaning "water", etc.*
- *Code positions: A set of integer references to characters in the repertoire.*
- Basic data types of an HTML document.
- Elements that govern the **structure** of an HTML document (text, list, table ...)
- Elements that govern the **presentation** of an HTML document (style sheet, font, color)
- Elements that govern **interactivity** with an HTML document (form, script)
- The SGML formal definition of HTML

## Document conventions

This document has been written with two types of readers in mind: **authors** and **implementors**.

### Reading Way
- Read from beginning to end
- Quick access to information

### Elements and attributes
- Element names are written in uppercase letters (e.g., BODY).
- Attribute names are written in lowercase letters (e.g., lang, onsubmit).
- Each attribute definition specifies the type of its value (If the type allows a small set of possible values, the definition lists the set of values, separated by a bar (|).)

### Notes and examples
- DEPRECATED EXAMPLE: all examples illustrating deprecated usage
- ILLEGAL EXAMPLE: all examples that illustrates illegal usage