Web Programming

The first web language, HTML (HyperText Mark-up Language), was developed in 1989 by Tim Berners-Lee, and was based on SGML (Standard Generalized Mark-up Language). In the beginning, content on the Web was static except for hyperlinking, and web developers aspired to make their websites more dynamic. In response to this need, several scripting languages were created - Netscape invented JavaScript, and Microsoft developed JScript and VBScript. (Floyd, 2000, Negrino, Smith, 1998). As Web programming and mark-up languages developed, interactivity and a richer visual online experience became more possible. By 1992, the web had incorporated "applets" and other types of active content. "Java's introduction in 1995 emphasized the delivery of applets through a browser to increase interactivity and a dynamic user experience." (O'Reilly, 2006).

The scripting or mark-up languages mentioned above, which run on the "client-side" computer, are only half the story. The other half of the story takes place on the server. By using server-side technologies and languages, such as CGI (Common Gateway Interface) and Perl, web pages can provide dynamic content, such as forms processing and database queries. In the early days of the Web, Perl and CGI were the most commonly used technology for client-server programming. Today there are many server-side alternatives to CGI, such as ASP (Active Server Pages), PHP, and ColdFusion, and these continue to gain in popularity. (Guelich, Gundavaram, Birznieks, 2000).

SGML - created in 1974 by Charles F. Goldfarb - was based on the OIM (Open Information Management) principles of data independence. (Floyd, 2000). According to Goldfarb, business databases - "which rigorously separate the real data from the input forms and output reports - achieved data independence decades ago." (qtd. Floyd, 2000). Documents have historically been created in the context of a particular program, such as Microsoft Word - making data independence more difficult. With the increased need to repurpose data into various formats, such as paper-based, web-based, and multimedia - simplified variations of SGML, such as HTML and XML (Extensible Mark-up Language) were developed. (Floyd, 2000). Current web languages and technologies emphasize the importance of separating structure from content, as a means to decrease development time and expense, and to facilitate data migration and transformation. Websites constructed with XML for data, XSLT (Extensible Stylesheet Lanaguage Transformations) for structure, CSS (Cascading Style Sheets) for design, and JavaScript for behavior, enable the complete separation of content and design. (Westin, 2004).

Using XML it is possible to create multi-purpose documents, which can be converted to:

1. a plain text file, useful for email,
2. XHTML file, to view within a browser,
3. WML (Wireless Mark-up Language) for display on a PDA (Portable Digital Assistant ),
4. an PDF (Adobe Portable Document Format) document for printing,
5. VML (Voice Mark-up Language) for a voicemail information system,
6. or SVG (Scalable Vector Graphics) useful for online or printed delivery. (Eisenberg, 2003).

The programming languages and technologies of Web 2.0 emphasize the ability to respond to constant change. One of these is the current popularity of RSS (Really Simple Syndication) content, which allows users to "subscribe" to a webpage and receive notification every time that page changes. This has been referred to as "the incremental web" or the "live web." (O'Reilly, 2006). Another significant aspect of Web 2.0 technology is database management as a core component, making Web 2.0 applications "infoware" rather than merely "software." (O'Reilly, 2006). As noted by O'Reilly:

…data is the next 'Intel Inside' [and] every significant internet application to date has been backed by a specialized database: Google's web crawl, Yahoo!'s directory, Amazon's database of products, eBay's database of products and sellers, and MapQuest's map databases. (O'Reilly, 2006).

According to O'Reilly, "…scripting languages such as Perl, Python, PHP, and now Ruby, play such a large role at Web 2.0 companies. Perl was famously described by Hassan Schroeder, Sun's first webmaster, as 'the duct tape of the internet'." (O'Reilly, 2006). Google uses a collection of technologies called AJAX, which really isn't a language or technology, it's a powerful combination of technologies incorporating:

1. standards-based presentation using XHTML and CSS;
2. dynamic display and interaction using the DOM (Document Object Model);
3. data interchange and manipulation using XML and XSLT (Extensible Stylesheet Language Transformations);
4. asynchronous data retrieval using XMLHttpRequest; and
5. JavaScript binding everything together. (O'Reilly, 2006).

With the advances in computer and network technology, and web programming, mark-up and scripting languages, the web has become a more complex and dynamic multimedia environment capable of serving up video, music, voice, text, images, data-processing, and interactive experiences. •