You Need to Know About CSS

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					         What You Need to Know About CSS!
Style sheet is a progressive breakthrough for the advancement of web. Today, more and more
browsers are implementing style sheets, opening authors' eyes to unique features that allow
influence over presentation while preserving platform independence. The advantages of style
sheets have become - apparent -- and the disadvantage of continually creating more HTML tags -
- galore -- for presentation effects with the gradual development of CSS.

Let's understand CSS in the right perspective.

Style sheets in retrospect

Style sheets have been around in one form or another since the beginnings of HTML in the early
1990s .

As the HTML language grew, however, it came to encompass a wider variety of stylistic
capabilities to meet the demands of web developers . With such capabilities, style sheets became
less important, and an external language for the purposes of defining style attributes was not
widely accepted until the development of CSS.

Teething problems with implementation of CSS

Many implementations of CSS are fraught with inconsistencies, bugs and other quirks . Authors
have commonly had to use hacks and workarounds in order to obtain consistent results across
web browsers and platforms .

One of the most well-known CSS bugs is the Internet Explorer box model bug; box widths are
interpreted incorrectly in several versions of the browser, resulting in blocks which appear as
expected in most browsers, but are too narrow when viewed in Internet Explorer. The bug can be
avoided, but not without some cost in terms of functionality.

This is just one of hundreds of CSS bugs that have been documented in various versions of
Internet Explorer, Netscape, Mozilla, and Opera many of which reduce the legibility of
documents. The proliferation of such bugs in CSS implementations has made it difficult for
designers to achieve a consistent appearance across platforms.

Currently there is strong competition between Mozilla's Gecko layout engine, Opera's Presto
layout engine , and the KHTML engine used in both Apple's Safari and the Linux Konqueror
browsers - each of them is leading in different aspects of CSS. Internet Explorer remains the
worst at rendering CSS by standards set down by World Wide Web Consortium as of 2005 .

Some breakthroughs ...

These problems have preisely led the W3C to revise the CSS2 standard into CSS2.1, which may
be regarded as something of a working snapshot of current CSS support. CSS2 properties which
no browser had successfully implemented were dropped, and in a few cases, defined behaviours
were changed to bring the standard into line with the predominant existing implementations..

What makes style sheets significant enough?

et representsStyle she an enormous step forward for the Web. With the separation of content and
presentation between HTML and style sheets, the Web no longer needs to drift away from the
strong ideal of platform independence that provided the medium with its initial push of
popularity. Authors can finally influence the presentation of documents without leaving pages
unreadable to users

A style sheet is made up of style rules that tell a browser how to present a document. There are
various ways of linking these style rules to your HTML documents, but the simplest method for
starting out is to use HTML's STYLE element. This element is placed in the document HEAD,
and it contains the style rules for the page.

Functionality and Usage of CSS

CSS is well-designed to allow the separation of presentation and structure. Prior to CSS, nearly
all of the presentational attributes of an HTML document were contained within the HTML
code; all font colors, background styles, element alignments, borders and sizes had to be
explicitly described, often repeatedly, in the midst of the HTML code.

CSS allows authors to move much of that information to a stylesheet, resulting in considerably
simpler HTML code. The HTML documents become much smaller and web browsers will
usually cache sites' CSS stylesheets. This leads to a reduction in network traffic and noticeably
quicker page downloads.

For example, the HTML element h2 specifies that the text contained within it is a level two
heading. It has a lower level of importance than h1 headings, but a higher level of importance
than h3 headings. This aspect of the h2 element is structural .

Customarily, headings are rendered in decreasing order of size, with h1 as the largest, because
larger headings are usually interpreted to have greater importance than smaller ones. Headings
are also typically rendered in a bold font in order to give them additional emphasis. The h2
element may be rendered in bold face, and in a font larger than h3 but smaller than h1 . This
aspect of the h2 element is presentational .

Prior to CSS, document authors who wanted to assign a specific color, font, size, or other
characteristic to all h2 headings had to use the HTML font element for each occurrence of that
heading type.

Moreover, CSS can be used with XML, to allow such structured documents to be rendered with
full stylistic control over layout, typography, color, and so forth in any suitable user agent or web
browser.
CSS has its share of inconsistencies as well

CSS may at times be misused, particularly by the author of web documents. Some developers
who are accustomed to designing documents strictly in HTML may overlook or ignore the
enabling features of CSS. For instance, a document author who is comfortable with HTML
markup that mixes presentation with structure may opt to use strictly embedded CSS styles in all
documents. While this may be an improvement over using deprecated HTML presentational
markup, it suffers from some of the same problems that mixed-markup HTML does; specifically,
it entails a similar amount of document maintenance.

Discrepancies compared: CSS vs programming languages

CSS also shares some pitfalls common with programming languages. In particular, the problem
of choosing appropriate names for CSS classes and identifiers may afflict CSS authors. In the
attempt to choose descriptive names for CSS classes, authors might associate the class name with
desired presentational attributes; for example, a CSS class to be applied to emphasized text might
be named "bigred," implying that it is rendered in a large red font.

While such a choice of naming may be intuitive to the document author, it can cause problems if
the author later decides that the emphasized text should instead be green; the author is left with a
CSS class called "bigred" that describes something that is green. In this instance, a more
appropriate class name might have been "emphasized," to better describe the purpose or intent of
the class, rather than the appearance of elements of that class.

In a programming language, such a misuse might be analogous to using a variable name "five"
for a variable which contains the value 5; however, if the value of the variable changes to 7, the
name is no longer appropriate.

CSS in a nutshell

CSS is used by both the authors and readers of web pages to define colors, fonts, layout and
other aspects of document presentation. It is designed primarily to enable the separation of
document structure (written in HTML or a similar markup language) from document
presentation (written in CSS).

This separation provides a number of benefits, including improved content accessibility, greater
flexibility and control in the specification of presentational characteristics, and reduced
complexity of the structural content. CSS is also capable of controlling the document's style
separately in alternative rendering methods, such as on-screen in print, by voice (when read out
by a speech-based browser or screen reader) and on braille-based, tactile devices.

CSS allows complete and total control over the style of a hypertext document. The only way this
can be illustrated in a way that gets people excited is by demonstrating what it can truly be, once
the reins are placed in the hands of those able to create beauty from structure.

				
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posted:10/26/2011
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