Trying to determine exactly which tags, attributes, and CSS properties work in every browser you need to support can be a time consuming and laborious task. However, thanks to the Dreamweaver MX 2004 Browser Target Check feature you can focus on building sites and let Dreamweaver worry about what will work in the browsers that you need to support.

This article also includes a nice little hack that you can apply to your style.css for Netscape 4.x, effectively hiding your styles and only using styles that work.

Read the Article

http://www.macromedia.com

Very nice, if only DW were not so expensive. I use it all the time at work and appreciate it. I just wish some of the open source editors, like Nvu, were up to speed on the some of its more advanced features (like the built in validators, esp. the accessibility checker).

However, you can get a lot of mileage out of your favorite text editor (Vim!) combined with Firefox and the Web Developer extension. It rocks - especially for working with CSS.