The problem is that there is no way of knowing what screen resolution (and what size display) the design will be viewed on. Too big, and lower resolutions will miss parts of it. Too small, and you waste valuable screen space. Learn the limitations of screen resolution, push them to the limit, but keep an eye on your audience.
What's it all about?
The "size" of screen is not so much limited by the physical dimensions of the display area but by the resolution at which that screen can display. Think of your screen as a grid made of tiny dots, called pixels. The more the screen can display, the higher the resolution.
But a monitor's resolution is not set in stone. Most can display at a variety of different resolutions, allowing the user to set it for their reading comfort. The physical dimension of the screen may be 15 inches but it might be able to display 640x480 or 800x600 pixels. A 21-inch monitor could also display 640x480 or 800x600 pixels but on a bigger monitor everything will look larger than with the same resolution on the smaller monitor. The higher the resolution, the more pixels get packed into the physical space accessible on screen so the larger monitor has more space and the size of each pixel is larger.
The resolutions that a computer screen can display depends on the type of monitor and the graphics capabilities.
Live screen space
For most web designers, height is not as vital as width. It's good to get the important information "above the fold" (the visible area of the screen when the page first loads), but vertical scrolling is okay but horizontal scrolling is taboo. Before beginning any web design decide which screen resolution the web page should fit comfortably (640x480 is the lowest common denominator and would ensure the widest audience). So, 640 pixels is the maximum width of the screen at that resolution, but this does not include the space taken up by the operating system and the browser window itself. The area you can use to display your site in the browser window is "the live space".
StatMarket has been monitoring websites around the world and collecting data on screen resolutions (www.statmarket.com). It found just 13 per cent on 640x480, 54 per cent on 800x600 and 26 per cent on 1024x768. Seven per cent is either higher resolution monitors or lower resolution monitors, including PDAs and mobile phones.
StatMarket says that its data is based on a virtually random sampling of more than 32.5 million website users worldwide. Not only is 640x480 only a small part of the market, StatMarket says it has fallen almost 30 per cent in the past year, a downward trend that is likely to continue.
The writer is the author of `DHTML For the World Wide Web'. If you have questions, you can find an archive of this column at www.webbedenvironments .com or send e-mails to: firstname.lastname@example.org