HTML and CSS Reference
HTML 4.0, first introduced in 1997, incorporated many new features that gave designers
greater control over page layout than HTML 2.0 and 3.2. Like HTML 2.0 and 3.2, the
W3C maintains the HTML 4.0 standard.
Framesets (originally introduced in Netscape 2.0) and floating frames (originally intro-
duced in Internet Explorer 3.0) became an official part of the HTML 4.0 specification.
Framesets are discussed in more detail in Lesson 17, “Working with Frames and Linked
Windows.” We also see additional improvements to table formatting and rendering. By
far, however, the most important change in HTML 4.0 was its increased integration with
If you're interested in how HTML development is working and just
exactly what's going on at the W3C, check out the pages for HTML
at the Consortium's site at
At one time, Microsoft and Netscape were releasing new versions of their browsers fre-
quently, competing to see who could add the most compelling new features to HTML
without waiting for the standards process to catch up. These days, browser releases in the
browser market are growing. Microsoft Internet Explorer and Mozilla Firefox are popu-
lar, and other browsers such as Apple Safari, Google Chrome, and Opera are in the mix,
too. Although they release new versions frequently, all of them are focused on imple-
menting web standards instead of introducing nonstandard features of their own. The
most important recent development, however, has been the expansion of the Web onto
mobile devices. Mobile phones and other devices are growing more powerful and popu-
lar, and it is becoming more important for web developers to consider these platforms
when designing their browsers.
The extra work involved in dealing with variations between browsers and platforms has
been a headache for web developers for a long time. Keeping track of all this information
can be confusing. Throughout this topic, as I introduce each tag, I explain any browser-
specific issues you may encounter.
XHTML 1.1 is written in Extensible Markup Language (XML) , and is the current
standard that most web developers adhere to. The X stands for XML, which is another
markup standard derived from SGML. The main difference from HTML is that XML
has strict rules for document structure. Whereas HTML 4 was forgiving of unclosed