Book HomeCascading Style Sheets: The Definitive GuideSearch this book Sunday 04th of December 2016 04:51:05 AM


The subject of this book is, as you might have guessed by the cover, Cascading Style Sheets (CSS). There are two "levels" to CSS; these are referred to as CSS1 and CSS2. The difference between the two is that CSS2 is all of CSS1, plus a lot more. This book attempts to cover all of CSS1, and CSS positioning, which is a part of CSS2. The rest of CSS2 is excluded because, at the time of this recognize <STYLE> and</STYLE>, it will ignore them altogether.However, the declarations within those tags willnot be ignored, because they will appear to beordinary text so far as the browser is concerned. So yourstyledeclarations will appear at the top of your page! (Of course, thebrowser should ignore the text because it isn't part of theBODY element, but this is never the case.) Thisproblem is illustrated in Figure 1-5. writing, nobody had implemented most of it. Rather than cover a lot of theoretical territory, we chose to stick to what was currently usable.

If you are a web designer or document author interested in sophisticated page styling, improved accessibility, and saving time and effort, then this book is for you. All you really need before starting the book is a decent knowledge of HTML 4.0. The better you know HTML, of course, the better prepared you'll be. You will need to know very little else in order to follow this book.

It is important to remember something about web standards and books: the former are continually evolving, while the latter are frozen in time (until the next edition comes out, anyway). In the case of HTML and CSS, there are a great many changes afoot even as these words are being written. The recent formalization of XHTML 1.0 as a full W3C Recommendation, for example, is a major milestone in the evolution of the World Wide Web. There are likely to be even more levels to CSS, further extending the ability to style documents; major web browsers are approaching full CSS1 support, and robust CSS2 implementations can be seen lurking on the horizon. This is an exciting time to be a designer, and learning CSS now will give you a leg up on the future.

0.1. Typographical Conventions

The following typographical conventions are used in this book:

Constant width

is used to indicate code examples, HTML tags and CSS elements.

Constant width italic

is used for replaceables that appear in text.


is used to introduce new terms and to indicate URLs, filenames, and pathnames.


indicates a note or tip relating to the nearby text.


indicates a warning.

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8.3. Floated Elements

As we saw in the previous chapter, CSSallows any element to be floated, from images to paragraphs to lists.This is not without a price: floated elements introduce their own setof strangeness. As was discussed, floated elements have an unusualplace in determining the flow of the document. For example, the boxesgenerated by other elements are drawn as though floated elementsdon't exist, but the content of those elements is renderedwhile taking the float's presence into account. This in turninfluences the generation of element boxes, which means that floats cell. In addition, there is a fourth table cell between the sidebarand the main part of the page, in order to create some blank space.There are also a lot of FONT tags and a few tablesimbedded within the main table that determines the page'slayout. The skeleton of the page is expressed as a table, with aborder and cell padding added to make the structure more clear:

This has the appearance shown in Figure 11-2.Obviously, there is a lot more in the cells than what's listedabove. The actual content was replaced by labels for the sake of