Though some web designers believe that Tables are a superior tool to CSS in designing lay out, this opinion is in the minority. Though CSS cannot be used to structure a website in itself, HTML or XHTML, should be used for this, it still should be the tool of choice when it comes to lay out for your website.
The download times with CSS are much faster than table lay outs. The reason for this is that when a table downloads, it carries far more amount of junk markup than CSS. This, as you can imagine, creates a much slower download time. A table which comprises of 140 lines of code, roughly equates to cascading style sheet of around 50 lines of code.
Additionally, CSS has a big advantage in terms of speed, as all the visual information is contained in a CSS file. Tables, store all the information that pertains to text, layout, and visual information, in the HTML, ASP, and PHP files. In other words Tables intergrate the information in these files. This creates a much slower download time for the website.
Cost can be a factor too in choosing to use CSS over Tables. Some web hosting companies charge to host a website based on its bandwidth. That is to say, that bandwidth, is the amount of traffic that is permitted to occur between your website and the rest of the internet.
As CSS designed sites tend to be half the size of Table designed websites, the bandwidth tends to be less. Additionally, with the use of external files, the bandwidth can be reduced further with CSS.
It is by far, much easier to redesign a CSS style sheet than it is a Table for the simple reason that CSS separates the visual information into its own file. This makes life much easier for a web designer, as they do not have to separate all the information as they do in Table design, which as mentioned earlier is integrated into the PSP, ASP, and HTML files.
This also means that is cheaper to redesign with CSS too. Especially if a web designer is being paid by the hour. Though it can be argued that CSS has browser specific bugs, most designers are familiar with them, and know how to over come the problems, which ensures that CSS redesigning is cheaper than Table redesigning.
Another reason to use CSS rather than Tables in web design, is that it is easier to retain consistency of the visual appearance of a site. Tables require columns widths, column height, texts, spacer gifs, and everything else to be edited page by page. Because CSS uses an external file, editing one or two elements, can result in the whole site being changed in a far shorter time, and consistency is assured. An additional advantage in using CSS to ensure visual consistency, is that it reduces the risk of error due to its simplicity.
CSS also has advantages over Table based designs, where search engine optimisation is concerned, or SEO. As CSS files have smaller file sizes, it is far easier and faster for search engines to search through a site to find those all important keywords. Remember there is less junk markup too, and this also makes it more easily searchable.
Another capability CSS has, is that it can bring search engine spiders to whatever it is a designer wants to show them by clever use of the h1, h2 tags. This combined with good SEO writing, makes CSS layouts that bit better than Table based designs.
If you are not yet convinced of the advantages CSS over Table layouts in web design, hopefully part two will do the trick.