Many authors recommend that during development, we should examine our pages with a variety of browser software. This also provides a form of learning for our students. The WWW ceases to be just a 'Netscape' thing or an 'Explorer' thing, when you use a variety of browsers with essentially identical results. Our undergraduates need a solid introduction to its syntax, its semantics and elements of style. It is our belief that the best way to teach HTML is by example.
Students readily grasp the syntax of a simple page.
Then by examining other pages, they extend their knowledge. Since our goal is communication, it is counter-productive to use language elements not recognized by all browsers. While we instruct the students to actively copy HTML elements from sites they enjoy, we do vigorously address the issue of intellectual property rights and copyright. Generally this is not a problem because of the 'gift mentality' still on the Web. Most authors take it as a compliment when asked if we can borrow an image or two from their site.