Web Page Design Guidelines

Use Advanced Features Sparingly
Don't use a feature just because it's there for you to use. For instance, don't use Frames (bordered areas of a browser window that can function as independent mini-browsers in their own right) when an ordinary table will do. Framed pages can be deathly slow.

Likewise, don't use Forms for free-form text or as a substitute for e-mail. They're a great way to let readers place orders, fill out questionnaires and reply to you with formatted information, but it's no fun typing running text into a small, vanilla Web window.

Before you build a site that requires a browser extension or plug-in/add-in, know that at best, many of your site visitors will have to download and install the plug-in/add-in before they can use your site. At worst, with a browser-specific plug-in/add-in, many of your visitors won't be able to access your site at all. 

Your safest bet is to be browser-neutral wherever possible. Even today, something like 30 percent of visitors to public sites don't use Netscape and that percentage is growing. If you do use a proprietary add-in/plug-in, provide a viable alternative for people with other browsers.