Book HomeCascading Style Sheets: The Definitive GuideSearch this book Monday 24th of November 2014 03:42:59 PM

Preface

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 writing, nobody had implemented most of it. Rather than cover a lot of theoretical territory, we chose to stick to what was currently usable. repeat-x:

BODY {background-image: url(yinyang.gif);
background-repeat: repeat-x;}

Now the image is repeated along the x-axis (in other words, horizontally), as illustrated in Figure 6-31.

Figure 6-31

Figure 6-31. Tiling along the horizontal axis

Finally, of course, we may wish not to repeat the background image at all. In that case, we use the last value,

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.

Italic

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

TIP

indicates a note or tip relating to the nearby text.

WARNING

indicates a warning.



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of the text is the same size. Just to cover all the bases, though, itmight make more sense to simply increase theline-height of the anchor element itself, likethis:

A:link {border: 5px solid blue; line-height: 24px;}P {font-size: 14px;}

If all the content of a line is text of the same size, then the linebox is always as tall as the biggest line-heightvalue contained within that line box (since this will coincide with |= will match a value that begins with thespecified value, given that the value is at the start of ahyphen-separated value. For example:

P[lang|="en"]

This selector will match any paragraph whose langattribute has the value en,en-US, en-UK,en-Cockney, and so on.