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Chapter 1. HTML and CSS


The Web's Fall from Grace
CSS to the Rescue
Limitations of CSS
Bringing CSS and HTML Together

In many ways, the Cascading Style Sheets (CSS) specification represents a unique development in the history of the World Wide Web. In its inherent ability to allow richly styled structural documents, CSS is both a step forward and a step backward -- but it's a good step backward, and a needed one. To see what is meant by this, it is first necessary to understand how the Web got to the point of desperately needing something like CSS, and how CSS makes the web a better place for both page authors and web surfers.

1.1. The Web's Fall from Grace

Back in the dimly remembered early years of the Web (1990 -1993), HTML was a fairly lean little language. It was almost entirely composed of structural elements that were useful for describing things like paragraphs, hyperlinks, lists, and headings. It had nothing even remotely approaching tables, frames, or the complex markup we assume is a necessary part of creating web pages. The general idea was that HTML would be a structural markup language, used to describe the various parts of a document. There was very little said about how these parts should be displayed. The language wasn't concerned with appearance. It was just a clean little markup scheme.

Then came Mosaic.

Suddenly, the power of the World Wide Web was obvious to almost anyone who spent more than ten minutes playing with it. Jumping from one document to another was no harder than pointing the mouse cursor at a specially colored bit of text, or even an image, and clicking the mouse button. Even better, text and images could be displayed together, and all you needed to create a page was a plain text editor. It was free, it was open, and it was cool.

Web sites began to spring up everywhere. There were personal journals, university sites, corporate sites, and more. As number of

Figure 7-84

Figure 7-84. Switching off image bullets in sublists


Remember that this may not be true in the real world: a user agent may have already defined a list-style-type for UL UL, so the value of square won't be inherited after all. Your browser may vary.

In the case of ordered lists, CSS2 goes a great deal sites increased, so did the demand for new HTML tags that would allow one effect or another. Authors started demanding that they be able to make text boldfaced, or italicized.

At the time, HTML wasn't equipped to handle these sorts of desires. You could declare a bit of text to be emphasized, but that wasn't necessarily the same as being italicized -- it could be boldfaced instead, or even normal text with a different color, depending on the user's browser and their preferences. There was nothing to ensure that what the author created was what the reader would see.

As a result of these pressures, markup elements like <B> and <I> started to creep into the language. Suddenly, a structural language started to become presentational.

1.1.1. What a Mess

Years later, we have inherited the flaws inherent in this process. Large parts of HTML 3.2 and HTML 4.0, for example, are devoted to presentational considerations. The ability to color and size text through the FONT element, to apply background colors and images to documents and tables, to space and pad the contents of table cells, and to make text blink on and off are all the legacy of the original cries for "more control!"

If you want to know why this is a bad thing, all it takes is a quick glance at any corporate web site's page markup. The sheer amount of markup in comparison to actual useful information is astonishing. Even worse, for most sites, the markup is almost entirely made up of tables and FONT tags, none of which conveys any real semantic meaning to what's being presented. From a structural standpoint, these pages are little better than random strings of letters.

For example, let's assume that for page titles, an author is using FONT tags instead of heading tags like H1, like this:

<FONT SIZE="+3" FACE="Helvetica" COLOR="red">Page Title</FONT>

Structurally speaking, the FONT tag has no meaning. This makes the document far less useful. What good is a FONT tag to a speech-synthesis browser, for example? If an author uses heading tags instead of FONT tags, the speaking browser can use a certain speaking style to read the text. With the FONT tag, the browser has no way to know that the text is any different from other text.

Why do authors run roughshod over structure and meaning like this? Because they want readers to see the page as they designed it. To use structural HTML markup is to give up a lot of control over a page's appearance, and it certainly doesn't allow for the kind of densely packed page designs that have become so popular over the years.

So what's wrong with this? Consider the following:

Granted, a fully structured document is a little plain. Due to that one single fact, a hundred arguments in favor of structural markup wouldn't sway a marketing department away from the kind of HTML so prevalent at the end of the twentieth century. What was needed was a way to combine structural markup with attractive page presentation.

This concept is nothing new. There have been many style sheet technologies proposed and created over the last few decades. These were intended for use in various industries and in conjunction with a variety of structural markup languages. The concept had been tested, used, and generally found to be a benefit to any environment where structure had to be presented. However, no style sheet solution was immediately available for use with HTML. Something had to be done to correct this problem.

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text is not a mistake on Explorer's part -- it's doingexactly as you specified. Basically, there isn't an easy way tocircumvent this problem, although two possible approaches aredetailed in Chapter 11, "CSS in Action".

Figure 7-27

Figure 7-27. Overlapping text in Explorer

It gets worse, unfortunately. If you apply margins to inlineelements, as was discussed previously, you'll get results fromNavigator 4.x like those shown in Figure 7-28.

H4 {border-style: dashed solid double;}
H4 {border: medium green;}

This will result in H4 elements having no border at all, because the lack of a border-style in the second rule means that the default value of none will be used. As we've seen, that will turn the border off altogether. Setting borders as quickly as possible

With all ofbut it's valid behavior.

Let's consider another example, illustrated in Figure 8-20, where the left margin is set to be negative:

DIV {width: 400px; border: 1px solid black;}
P.wide {margin-left: -50px; width: auto; margin-right: 10px;
border: 3px solid gray;}
Figure 8-20

Figure 8-20. Setting a negative left margin

In this case, not only does the paragraph spill beyond the borders of the DIV, but also beyond the edge of the browser to float outside of their parent's content area. It also makesit seem like the term "containing block" should really be"positioning context," but since the specification uses"containing block," so will this text. (We do try tominimize confusion. Really!)

9.1.1. Positioning Schemes

You canchoose one of four different types of positioning by using the


padding-topIE4 P/P IE5 P/Y NN4 B/B Op3 Y/-

This property sets the size of the top padding of an element, and this padding will "inherit" the element's background. Negative values are not permitted.


text-alignIE4 Y/P IE5 Y/Y NN4 Y/P Op3 Y/-

This sets the horizontal alignment of the text in an element, or more precisely, defines to which side of the element the line-boxes are aligned. The value