Benefits of CSS
- After switching to a CSS layout the average page size is decreased by 60%
- Faster download and rendering time
- More search engine-friendly
- More print-friendly
CSS downloads faster than tables because:
- Browsers read through tables twice before displaying their contents, once to work out their structure and once to determine their content
- Tables appear on the screen all in one go - no part of the table will appear until the entire table is downloaded and rendered
- Tables encourage the use of spacer images to aid with positioning
- CSS generally requires less code than cumbersome tables
- All code to do with the layout can be placed in an external CSS document, which will be called up just once and then cached (stored) on the user's computer; table layout, stored in each HTML document, must be loaded up each time a new page downloads
- With CSS you can control the order items download on to the screen - make the content appear before slow-loading images and your site users will definitely appreciate it
- More accessible
- The number of users browsing the web through handheld devices is growing massively. In 2008 alone an estimated 58 million PDAs will be sold (source: eTForecast3) and one third of the world's population will own a wireless device (source: ClickZ4). You can make an additional CSS document specifically for handheld devices, which will be called up in place of the regular CSS document. This is not possible with a tabular layout.
More search engine-friendly
Search engines can often spider CSS-driven web pages more easily as they usually have simpler, better structured HTML code. The search engine can then make a more educated guess as to what the web page is about, so all other things being equal, your web pages will appear higher in the search rankings with a CSS layout.
When a user chooses to print a web page an alternative CSS document can be called up. This document can specify that formatting, images and navigation disappear and just the page content appear on the printed version.