Beginning HTML, XHTML, CSS, and JavaScript®

Appendix I. Deprecated and Browser-Specific Markup

As the versions of HTML and XHTML have developed, quite a lot of markup has been deprecated, which is the W3C's way of alerting web developers that is is likely to be removed from future versions of HTML and XHTML and that web-page authors should stop using it (although there is an acknowledgment that some people may still need to use it for a while). Where markup is deprecated, there is usually an acceptable alternative way to achieve the same goal (in many cases using CSS).

You can still use quite a lot of the deprecated markup that you meet in this chapter when using the Transitional XHTML DOCTYPE, but Strict XHTML has already removed most of the elements and attributes that affect presentation of elements.

I have included the details of these elements and attributes in this book, despite the fact that the markup is deprecated or out of date, because you are likely to come across it in other people's code, and on very rare occasions you might need to resort to using some of this markup in order to get a specific job done.

In addition to deprecated markup, I will introduce some of the browser-specific markup that you may come across. This is markup that browser manufacturers added to their browsers to allow users to do more things than they could in competing browsers — but these browser-specific elements and attributes never made it into the HTML recommendations, and are therefore referred to as browser-specific markup.

This appendix ...