Mastering Web Technologies: XHTML, CSS, and AJAX Components
Classified in Computers
Written on in 
English with a size of 2.25 KB
Core Web Technologies Explained
XHTML: Structured Markup
XHTML is HTML based on XML. With it, you can combine HTML markup with XML rules. The idea is to have a standardized document and to be made accessible across multiple platforms and devices, such as a computer desktop, PDA, mobile phone, or TV.
CSS: Appearance Standards
CSS (Cascading Style Sheets) is another important technology. With CSS, you can set standards for the appearance and behavior of page elements. The colors, paragraphs, margins, spacing, thickness, or other page elements can be defined in one file. Therefore, at any time, you can totally change the way all pages of a site look by simply changing the file that contains the CSS definitions. This feature, in conjunction with AJAX, makes it possible to dynamically change the site's appearance to fit the tastes of each user.
XML and Data Handling
XML or Extensible Markup Language is one of the pillars of AJAX (more precisely, the 'X'). It is through XML that we can manipulate page elements (such as DOM elements) or process server responses.
XSLT for Transformation
XSLT is a language for transforming XML documents. With it, XML documents can be transformed into another document, or elements can be included, changed, or even deleted. XSLT is a declarative language where you can specify rules to transform an XML file into the desired format. Combining XSLT with JavaScript, you can dynamically modify a document, seek information from the server, build the presentation format, and show the final result on an HTML page, thereby utilizing AJAX features.
XMLHttpRequest: The AJAX Engine
XMLHttpRequest is the object that connects the page asynchronously to the Web application server; it is the core technology of AJAX—without it, AJAX does not exist. This is a JavaScript object that can be used to make requests to the Web server in the background without freezing the browser or reloading the current page. The XMLHttpRequest object is now part of the DOM Level 3 specification. That is, any browser that wants to support the standards must implement the XMLHttpRequest object.