This document answers questions asked frequently by web authors. While its focus is on HTML-related questions, this FAQ also answers some questions related to CSS, HTTP, JavaScript, server configuration, etc.
This document is maintained by Darin McGrew <darin@htmlhelp.com> of the Web Design Group, and is posted regularly to the newsgroup comp.infosystems.www.authoring.html. It was last updated on April 26, 2007.
The World Wide Web is "the universe of network-accessible information (available through your computer, phone, television, or networked refrigerator...)." The World Wide Web began as a networked information project at CERN.
HyperText Markup Language is a simple markup language used to create platform-independent hypertext documents on the World Wide Web. Most hypertext documents on the web are written in HTML.
The latest W3C recommendation is XHTML 1.0, which is a reformulation of HTML 4.01 as an XML 1.0 application. HTML 4.01 is an update with minor corrections to HTML 4.0. HTML 4 extends HTML 3.2 to include support for frames, internationalization, style sheets, advanced tables, and more. The new markup introduced by HTML 4 is not well supported by current browsers, but much of it can be used safely in non-supporting browsers.
Cascading Style Sheets are a standards-based mechanism for suggesting presentational style (e.g., fonts, colors, layout) for HTML documents. CSS is flexible and cross-platform, and is designed to preserve the accessibility of the document's structural content (even when all or part of the author's style sheet is ignored). A single style sheet can be used by multiple documents to suggest a common cohesive style, which is more efficient than using repetitive presentational markup in each individual document.
Standard Generalized Markup Language is a language used to define the syntax of markup languages. HTML is an SGML application (a markup language defined in SGML).
Extensible Markup Language is another language used to define the syntax of markup languages. XML is a subset of SGML, and is designed to represent arbitrary structured data in a text format. XSL is a stylesheet language for styling XML documents.
Extensible HyperText Markup Language reproduces, subsets, and extends HTML, reformulated as an XML application. XHTML 1.0 is identical to HTML 4.01, except for the syntax requirements imposed by XML. XHTML Basic is a minimal subset of XHTML for Web clients with limited capabilities. XHTML 1.1 is a reformulation of XHTML 1.0 Strict using XHTML Modules.
Server-Side Includes allow various directives (e.g., to include the content of another file) to be embedded within web documents. The web server processes SSI directives each time a document that uses SSI is retreived. Documents that use SSI are often identified with a .shtml filename extension, but there is no "SHTML" language as such. Implementation details vary among web servers; consult your server documentation for details.
Common Gateway Interface is a standard interface between external programs and web servers. Unlike static HTML documents, CGI programs can produce dynamic information based on form data submitted by the user, on information in a database, or on any other data available to the program.
Note that while many CGI programs are written in Perl, CGI programs can be written in other languages as well (including C, C++, Python, Visual Basic, and various Unix shells).
PHP: Hypertext Preprocessor is a general-purpose cross-platform scripting language. PHP is often used for embedded server-side scripts in dynamic web pages.
JavaScript is a cross-platform, interpretted, object-oriented language originally designed for client-side web scripting. The elements of web pages can be manipulated via JavaScript as objects specified by the Document Object Model (DOM). This enables dynamic effects like image roll-overs and interactive effects like pages that change in response to user input without being reloaded from the server.
LiveScript was Netscape's initial pre-release name for JavaScript. JScript is Microsoft's implementation of the language. ECMAScript is a standardized version based upon Netscape's JavaScript and Microsoft's JScript.