The Hyper Text Markup Language (HTML)

Here's a link to the latest HTML specification:

Markup languages allow users to annotate documents.

Annotations may refer to the content of a document (for example XML) or the presentation of the document (for example HTML).

An HTML document has a tree-like structure of elements nested inside of elements.

The format of an HTML document is described here.

Examples of HTML elements are given here.

Links and Hypertext

Hypertext has a history that predates HTML. Ordinary texts store information in a linear format, while humans store information in a network in which nodes (beliefs) are linked if they related in some way. The idea is that this creates a kind of impedance mismatch when we read. To overcome this mismatch, a hypertext system allows users to easily access all documents in a repository that a given document might reference. An example of this might be a set of encyclopedias in which one article contains references to other articles.

Formally, HTML links are called anchors. Here's an example:

<a href = "http://www.unc.edu">Click Here</a>

Scripts

A script is a snippet of code that is embedded in a web page. Client-side scripts are executed by the browser. Server-side scripts (like JSP) are executed by the server.

A client side script has the format:

This kind of script will be executed once, when the document is loaded.

Scripts are useful for validating user input on a form.

The Javascript language is discussed here.

Objects

Examples of objects that can be embedded in an HTML document include images, video clips, applets, and other web pages. Source and other information about the object are specified using the Object tag:

Forms

A UML Model of HTML

This is a simplification of the W3C Document Object Model (DOM).