CSS for layout

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… and why you should use it.

Separating content from structure and style is a common theory, widely accepted to those of us either using or investigating single source solutions for our documentation. The same theory has been applied to web development and offers similar benefits.

CSS-based web design developed in parallel with the growing movement towards (and promotion of) the use of standards on the web. The web standards movement was a direct response to the increasing problems faced by web designers as they struggled to keep pace with the bespoke features introduced by the browser software of the day. Advocating support for the W3 maintained standards around, initially, HTML it soon found a band of supporters who were challenging themselves, and everyone else, to stop using tables as a mechanism for controlling page layout, and instead switch to using Cascading Style Sheets (CSS).

The origin of table-based layout was, essentially, a clever hack. Early versions of HTML, and the internet browsers that people used to view web pages didn’t have any way to control the layout of a page so tables were used. Nesting tables within tables to provide discrete areas for navigation, content and so on, became the norm and some very complex examples still exist. However, as the web gained popularity and large sites started to emerge, it became apparent that table-based layout were no longer workable. They were far too hard and too time consuming to maintain, and many web developers recognised this and started searching for a solution.

Separating the content from the layout elements was an obvious step and is easily achieved using CSS. Whilst it was primarily created to allow more flexible and powerful styling, it was soon evident that, as each page element can have positioning assigned, that it could also be used as the positioning mechanism.

The basic theory of CSS-based layout is pretty simple. If you draw out the sections of your web page you’ll probably end up with several different blocks. One for the banner, one for the navigation, another for secondary navigation, one for the content, and so on. Each of those blocks can be positioned separately, or in relation to one another and as each block is uniquely identified division, then all you need to do is apply layout rules to every division to position it where you want. OK, maybe it’s a little flippant to say “all you need to do” as there is a wealth of issues to be aware of when using CSS for layout but don’t panic, there are plenty of templates to get you started, I’ve linked to some at the end of this post.

Mind you, this doesn’t really sound much different from using tables though. Right?

Wrong. The real power of using CSS for layout comes when you need to change the position or other layout characteristics of one of those divisions. For example, let’s say you have a set of navigation links in a column down the left of the page. In a table-based layout you’d have a separate table cell holding those links (which may in turn be held in a nested table to help you align them). Simple enough.

Now, you need to switch that list of links to the right of the page. In table-based layout you’d need to cut-n-paste that table cell and move it on EVERY PAGE in your website or across your help system. Do you fancy doing that for every page in a 500 page help system, because I don’t.

Using CSS for layout, you’d make a change to the stylesheet (the .CSS file) and all the pages in your website would be updated. For a large website, or for anything more than 20 or so pages, the time savings soon become evident. I’d advocate that you take this approach for smaller static websites as whilst, table-based layout is still possible, the repetition of making any minor layout change still needs to be reflected across every page.

Ultimately, using CSS for layout isn’t really about web standards, nor is it just a trend. It’s a justified and valid use of technology to allow you to work smarter, to concentrate on the content you are delivering, and not spend a disproportionate amount of time editing multiple pages of a web-based help system or website. When your boss asks you what you did last week, what would YOU rather say?

Learning CSS-based layout is not without problems, there are still browser compatibility issues to overcome, although most are now well documented and easy to grasp but I truly believe that it is worthwhile learning the basics. Of course, the internet being what it is, there are a myriad of templates available to get you started, in fact some may even provide all you need.

Related reading:
Layoutomatic – offers three simple CSS-based layouts. A good way to learn the basics.
Free CSS layouts and templates – compiled by the wonderful Smashing Magazine.
Web Standards Project – keep up to date with the latest news in web standards.
CSS Zen Garden – one structured page of content, hundreds of different CSS layouts and styles. THE example of the power of CSS-based layout.
A List Apart – an excellent online magazine for web design, chock full of good stuff.