Datasheet

❑ The presentation of an entire website can be centralized to one or a handful of documents,
enabling the look and feel of a website to be updated at a moment’s notice. In legacy HTML
documents, the presentation is contained entirely in the body of each document. CSS brings a
much needed feature to HTML: the separation of a document’s structure from its presentation.
CSS can be written independently of HTML.
❑ Users of a website can compose style sheets of their own, a feature that makes websites more
accessible. For example, a user can compose a high-contrast style sheet that makes content
easier to read. Many browsers provide controls for this feature for novice users, but it is CSS
nonetheless.
❑ Browsers are beginning to support multiple style sheets, a feature that allows more than one
design of a website to be presented at the same time. The user can simply select the look and
feel that he or she likes most. This could only be done previously with the aid of more complex
programming languages.
❑ Style sheets allow content to be optimized for more than one type of device. By using the same
HTML document, different versions of a website can be presented for handheld devices such as
PDAs and cell phones or for printing.
❑ Style sheets download much more quickly because web documents using CSS take up less hard
disk space and consume less bandwidth. Browsers also use a feature called caching, a process
by which your browser will download a CSS file or other web document only once, and not
request that file from the web server again unless it’s been updated, further providing your
website with the potential for lightning-fast performance.
Cascading style sheets allow the planning, production, and maintenance of a website to be simpler than
HTML alone ever could be. By using CSS to present your web documents, you curtail literally days of
development time and planning.
Summary
Cascading style sheets are the very necessary solution to a cry for more control over the presentation of a
document. In this chapter, you learned the following:
❑ The World Wide Web Consortium plans and discusses how the Internet should work and
evolve. CSS is managed by a group of people within the W3C called the CSS Working Group.
This group of people makes recommendations about how browsers should implement CSS
itself.
❑ The Internet is a complex network of computers all linked together. When you request a web
document, that request travels through that network to a computer called an HTTP server that
runs software. It sends a response containing the page you requested back through the network.
Your browser receives the response and turns it into something you can see and interact with.
❑ CSS answers a need for a style sheet language capable of controlling the presentation of not only
HTML documents, but also several types of documents.
❑ Internet Explorer 6, Gecko, Opera, and KHTML browsers make up the majority of browsers in
use today, with Internet Explorer 6 being the world’s most popular browser.
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Part I: The Basics
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