Web page text has many of the formatting options available in a word processor. These include applying fonts, emphasis (bold, italic, underline) and placing information in tables. Formatting is possible since the web browser applies these formats according to instructions that are contained in the file that makes up the web page. This is usually written in HTML or Hypertext Markup Language.
HTML is an international standard established by the World Wide Web Consortium (published at www.w3.org) and intended to ensure that any web page written according to the definitions in the standard will appear the same in any web browser. A simple example of HTML is given for a simplified home page for a B2B company in Figure 1.15. The HTML code used to construct pages has codes or instruction tags such as.
Text information and data – XML (Extensible Markup Language)
When the early version of HTML was designed by Tim Berners-Lee at CERN, he based it on the existing standard for representation of documents. This standard was SGML, the Standard Generalized Markup Language which was ratified by the ISO in 1986. SGML uses tags to identify the different elements of a document such as title and chapters. HTML used a similar approach.
Graphical images (GIF, JPEG and PNG files)
Graphics produced by graphic designers or captured using digital cameras can be readily incorporated into web pages as images. GIF (Graphics Interchange Format) and JPEG (Joint Photographic Experts Group) refer to two standard file formats most commonly used to present images on web pages. GIF files are limited to 256 colors and are best used for small simple graphics, such as banner adverts, while JPEG is best used for larger images where image quality is important, such as photographs. Both formats use image compression technology to minimize the size of downloaded files.
Portable Network Graphics is a patent and license-free standard file format approved by the World Wide Web Consortium to replace the GIF file format.b