HTML
HTML is an acronym for HyperText Markup Language, the authoring language used to create documents on the World Wide Web.
HTML defines the structure and layout of a Web document by using a variety of tags and attributes. The correct structure for an HTML document starts with <html> and <head> (enter here what document is about) </head> <body> tags and ends with </body> </html> tags. All the information you'd like to include in your Web page fits in between the <body> and </body> tags.
There are hundreds of other tags used to format and layout the information in a Web page. For instance, <p> ... </p> is used to make paragraphs and <i> ... </i> is used to italicize fonts. Tags are also used to specify hypertext links. These allow Web developers to direct users to other Web pages with only a click of the mouse on either an image or word(s).
In our courses we insist on matching the HTML 4.01 specification (the last HTML specification to be published -- the latest specification is XHTML 1.0). The Web constantly evolves.
For more on HTML link to W3schools and then close this window.
XML
XML is an acronym for Extensible Markup Language. XML allows designers to create their own customized tags, enabling the definition, transmission, validation, and interpretation of data between applications and between organizations.
XML also fully separates content from formatting -- the XML file contains the data; a stylesheet contains the formatting. XML is open source scripting - no single vendor owns the rights to XML. XML is "extensibile" - programmers create their own sets of “tags” depending on the specific needs of a document.
XML was approved by the World Wide Web Consortium (W3C) in February, 1998. XML is new, but the underlying technology has been under development for over a decade.
The first step in making XML the new language of the Web was the creation of XHTML by W3C. XHTML 1.0 if the latest specification - HTML 4.01 was the last HTML specification but HTML 5 is sitting on the horizon which may mean that XHTML has a limited life.
For more information on XML, link to XML.com and then close this window.
Web Graphics
Many Web designers, even some professionals in the industry, do not realize that you can reduce images to a fraction of their original filesize without significantly compromising image quality. This process is known as "image optimization."
In a single sentence, image optimization involves obtaining the best quality image for your purpose at the smallest filesize (and resulting shorter download time). Simply defined, image optimization involves locating the correct compression settings to make the image as small as possible with as little loss of resolution as you can get away with. Why is this necessary? Because it take time for images to be loaded (most people are accessing the Internet over dialup connections, after all) and optimization reduces that time.
Graphics images on the internet come in three major formats: GIF, JPEG and PNG (and PNG's close relation MNG). Each of these formats has it's associated advantages and disadvantages. It is important that you understand all three formats to make the correct decision as to which to use under what circumstances.
For more information, see "Optimizing Web Graphics" and then close this window.
Audio/Video
Because there has been no effort to standardize audio and video media for Web delivery, adding these elements to your Web pages can sometimes be difficult. There are more than a dozen file formats available, at least half a dozen media players, and literally hundreds of compression codecs (coder/decoders). It is impossible to deliver raw (i.e., uncompressed) audio and video on the Internet so the use of codecs is mandatory.
Probably the first audio file format developed for Internet delivery was Sun Microsystems AU file format. AU was followed quickly by several new formats including AIFF and WAVE, and the proprietary formats QuickTime (.mov), RealAudio (.ra, .rm), and several Windows Media formats. Several codecs are available to compress audio in each of these formats, including ADPCM, A-law, μ-law (mu-law), IMA, QDesign, PureVoice, the RealMedia codecs, and many others. MPEG (both a format — mp3 and mp4 — and a compression codec, MPEG-3, MPEG-4, etc.) has recently become the most popular audio format. There is also MIDI, which is a very special audio format.
Web video lacks similar standardization. MDIA 3206 will help you sort out some of these problems.
For more information on audio and video, link to Using Audio and Video and then close this window.
Flash
Flash is a bandwidth-friendly and browser-independent vector-graphic animation technology. As long as different browsers are equipped with the necessary plug-ins, Flash animations will look the same. With Flash, users can draw their own animations or import other vector-based images.
Flash uses a vector graphics technology that allows for interactive presentations that can adapt to various display sizes and resolutions. This allows your Web pages to be sized as needed (if allowed by the designer).
Flash Player let’s you view interactive illustrations and games, animations, and even complete websites that have been designed in this format. Adobe’s Shockwave is a high-end player that offers such features as multiuser chat, XML parsing, HTML manipulation, an extensive and fast scripting language, distant file retrieval, programmatic control of vector shapes, and bitmap manipulation.
For more information on Flash, link to Some Considerations When Using Flash for Web Pages and then close this window.
JavaScript
JavaScript is scripting language developed by Netscape to enable Web authors to design interactive sites. Although it shares many of the features and structures of the full Java language, it was developed independently. Javascript can interact with HTML source code, enabling Web authors to spice up their sites with dynamic content. JavaScript is endorsed by a number of software companies and is an open language that anyone can use without purchasing a license. It is supported by recent browsers from Netscape and Microsoft, though Internet Explorer supports only a subset, which Microsoft calls Jscript.
For more information on JavaScript visit JavaScript.com and then close this window.
CSS — Cascading Style Sheets
Cascading Style Sheets (CSS) is a style sheet language used to describe the presentation semantics (the look and formatting) of a document written in a markup language. Its most common application is to style Web pages written in HTML and XHTML, but the language can also be applied to any kind of XML document, including SVG and XUL.
CSS is designed primarily to enable the separation of document content (written in HTML or a similar markup language) from document presentation, including elements such as the layout, colors, and fonts. This separation can improve content accessibility, provide more flexibility and control in the specification of presentation characteristics, enable multiple pages to share formatting, and reduce complexity and repetition in the structural content (such as by allowing for tableless web design). CSS can also allow the same markup page to be presented in different styles for different rendering methods, such as on-screen, in print, by voice (when read out by a speech-based browser or screen reader) and on Braille-based, tactile devices. While the author of a document typically links that document to a CSS style sheet, readers can use a different style sheet, perhaps one on their own computer, to override the one the author has specified.
CSS specifies a priority scheme to determine which style rules apply if more than one rule matches against a particular element. In this so-called cascade, priorities or weights are calculated and assigned to rules, so that the results are predictable.
For more information on CSS, link to Wikipedia and then close this window.
PHP
PHP Hypertext Preprocessor is an open-source (i.e., free) server-side scripting language for creating dynamic Web pages for e-commerce and other Web applications. A dynamic Web page is a page that interacts with the user, so that each user visiting the page sees customized information. Dynamic Web applications are prevalent in commercial (e-commerce) sites, where the content displayed is generated from information accessed in a database or from some other external source.
PHP provides an easy way to accomplish Web-related programming tasks, which are accomplished only with difficulty in more complex and powerful languages, such as Perl or C. It is ideally suited to the Web because PHP scripts live inside Web pages right along with the HTML tags and content. For that reason, PHP is called an embedded scripting language.
PHP performs essentially the same functions as Microsoft's ASP technology, but does not depend so much on proprietary Microsoft software. For example, database connectivity in ASP works best with Microsoft Access while PHP works well with a wide variety of database applications but works especially well with mySQL, a database environment which is free to most users.
For more on PHP visit PHP.net and then close this window.
AJAX
AJAX (shorthand for Asynchronous JavaScript and XML) is a group of interrelated web development methods used on the client-side to create interactive Web applications. With AJAX, Web applications can retrieve data from the server asynchronously in the background without interfering with the display and behavior of the existing page. Data is usually retrieved using the XMLHttpRequest object. Despite the name, the use of XML is not needed, and the requests need not be asynchronous.
Like DHTML and LAMP, AJAX is not one technology, but a group of technologies. AJAX uses a combination of HTML and CSS to mark up and style information. The DOM is accessed with JavaScript to dynamically display, and to allow the user to interact with, the information presented. JavaScript and the XMLHttpRequest object provide a method for exchanging data asynchronously between browser and server to avoid full page reloads.
For for information on AJAX, link to Wikipedia and then close this window.