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tags: HTML4 SPEC
---
# Section 2:Introduction to HTML 4

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

## Table of contents
- [What is the World Wide Web?](#What-is-the-World-Wide-Web?)
- [What is HTML?](#What-is-HTML?)
- [HTML 4](#HTML-4)
- [Authoring documents with HTML 4](#Authoring-documents-with-HTML-4)

## What is the World Wide Web?
`a network of information resources`
- **relies on 3 mechanisms**
1. uniform naming scheme for locating resources on the Web(e.g., **URIs**) #統一資源標識符
2. Protocols, for access to named resources over the Web(e.g., **HTTP**)
3. Hypertext, for easy navigation among resources(e.g., **HTML**)

- **Introduction to URIs**
`Encode every resource available on the Web`
- consist of 3 pieces
1. The naming scheme of the mechanism used to access the resource.
2. The name of the machine hosting the resource.
3. The name of the resource itself, given as a path.

ex. `http://www.w3.org/TR`
- **Fragment identifiers**
- ex. `http://somesite.com/html/top.html#section_2`
- **Relative URIs**
- doesn't contain any naming scheme information. Its path generally refers to a resource on the same machine as the current document.

## What is HTML?
`universally understood language to publish information for global distribution`
- **A brief history of HTML**
- During the course of the 1990s it has blossomed with the explosive growth of the Web
- HTML 2.0、HTML+、HTML 3.0、HTML 3.2
- greater consensus
- all manner of devices should be able to use information on the Web

## HTML 4
`style sheets`
`scripting`
`frames`
`embedding objects`
`improved support for right to left and mixed direction text`
`richer tables`
`enhancements to forms`
- **Internationalization**
- diverse human languages within a document
- effective indexing of documents for search engines
- higher-quality typography
- better text-to-speech
- better text-to-speech conversion
- better hyphenation
- **Accessibility**
`more accessible to those with physical limitations`
- Better distinction between document structure and presentation
- Better forms
- markup a text description of an included object
- A new client-side image map mechanism
- IMG element & AREA element
- Support for the title and lang attributes on all elements.
- Support for the ABBR and ACRONYM elements.
- A wider range of target media (tty, braille, etc.) for use with style sheets.
- Better tables
- Long descriptions of tables, images, frames, etc.

- **Tables**
- greater control over structure and layout
- **Compound documents**
- a standard mechanism for embedding generic media objects and applications in HTML documents
- **Style sheets**
- presentation
- individual/groups elements
- in an HTML document or in external style sheets.
- **Scripting**
- dynamic Web pages
- **Printing**
- the HTML LINK element
- W3C's Resource Description Framework (RDF)

## Authoring documents with HTML 4
- **Separate structure and presentation**
- HTML’s presentational elements and attributes are being replaced
- reduces the cost of serving a wide range of platforms, media, etc.
- facilitates document revisions.

- **Consider universal accessibility to the Web**
- consider how their documents may be rendered on a variety of platforms
- speech-based browsers
- braille-readers
- interpreted correctly
- include in their documents information about the natural language and direction of the text
- how the document is encoded

- **Help user agents with incremental rendering**
- Authors can learn how to design tables for incremental rendering