HTML and XHTML: What’s the difference ?

HTML is Hypertext Markup Language, a notation developed in the late 1980s
and early 1990s for describing Web pages. HTML is now enshrined in numerous
standard descriptions (specifications) from the World Wide Web
Consortium (W3C). The last HTML specification was finalized in 1999.
The formal documents to describe HTML and XHTML are on the W3C’s Web site at www.w3.org.

HTML and XHTML specifications
Markup languages usually include version numbers to identify them. The current version of HTML
is 4.01. It dates back to December 1997; you can find the document at www.w3.org/TR/html4.
XHTML has gone through two major drafts, 1.0 and 1.1. The 1.1 version is more advanced than 1.0,
but most Web content developers and software tools follow the 1.0 specification. An XHTML 2.0
specification is in “Working Draft” status (its authors haven’t finalized its content and structure).
When a W3C specification is finished, it’s known as a W3C Recommendation.
You can find specifications for all three versions of XHTML:
 XHTML 2.0 Working Draft (7/4/2004)
www.w3.org/TR/2004/WD-xhtml2-20040722/
 XHTML 1.1 Module-based XHTML Recommendation (5/31/2001)
www.w3.org/TR/xhtml11/
 XHTML 1.0 Recommendation (1/26/2000)
www.w3.org/TR/xhtml1/
Reading W3C specifications takes some learning and improves with repeated exposure. Don’t let
the formal language and notation of these documents put you off: After you understand what’s up,
you appreciate the precision and detail! But you may decide never even to look at one of these
specifications — it’s entirely up to you!
The HTML 4.01 specification is the rulebook of HTML, as the XHTML 1.0 specification is for XHTML —
each one tells you exactly which elements you can use, which attributes go with those elements, and
how you use elements in combinations to create such page structures as lists, forms, tables, and
frames. This blog uses the XHTML 1.0 specification as its basis


When you put an X in front of HTML to get XHTML, you get a new, improved
version of HTML based on the eXtensible Markup Language (XML). XML is
designed to work and behave well with computers, software, and the
Internet.
The original formulation of HTML has some irregularities that can cause
heartburn for software that reads HTML documents. XHTML, on the other
hand, uses an extremely regular and predictable syntax that’s easier for software
to handle. XHTML will replace HTML someday, but HTML keeps on ticking.
This Blog covers both varieties and shows you the steps to put the X in
front of your own HTML documents and turn them into XHTML.
Most HTML and XHTML markup is identical.
In a few cases, HTML and XHTML markup looks a little different.
In a few cases, HTML and XHTML markup must be used differently.

Keep checking for more,I keep it updated everyday
;).