HTML/XHTML Markup Languages

HTML/XHTML, which stands for HyperText Markup Language and eXtensible HyperText Markup Language, are two popular markup languages for designing web pages. Tim Berners-Lee defined the original version of HTML and wrote a browser to support it in time frame around 1990.

HTML is a markup language that consists of tags within open and close angle brackets which enclose data that describes a web page. Angle brackets are less-than symbols and greater-than symbols, the less-than symbol being the open bracket and the greater-than symbol being the close bracket. Tags are used to define headers, paragraphs, images, blocks of code, etc. Some tags require an open and close tag; some tags need not be closed. Attributes may be defined within the open tag. Cascading Style Sheets (CSS) may be used to refine the data enclosed within the tags by specifying appearance and positioning of the data in the formatted web page. JavaScript is a popular scripting language that allows dynamic content to be used within an HTML web page. XHTML is a markup language using the same tags as HTML; however XHTML abides by the formal XML specifications in the markup language.

There has been some controversy involved in the use of HTML tables in positioning elements in a web page. Many people advocate the use of CSS positioning capabilities in web page layout. In accomplishing this goal, the web designer would use the <div> tag along with the position and float attributes, together with the corresponding CSS definitions and values. The advocates of this strategy point out that those who use this strategy are able to more quickly create, change, and modify the appearance of the web page presentation.

The browser is the tool that displays websites presented in HTML/XHTML. Internet Explorer, a Microsoft product, dominates the market. Netscape's browser, Navigator, dominated the market in the early days of the World Wide Web, but was displaced by Internet Explorer. The remnants of Navigator have been moved over to a browser named Mozilla Firefox, an open source software project. In 2003, Apple released a beta version of a browser named Safari, and since then has released a version that supports Windows operating systems. Google introduced a new browser named Chrome in 2008. America On Line (AOL) has a browser named AOL Explorer. Other popular browsers include Opera and Konquerer.