Head First HTML with CSS

What is XML?
Okay, we’re going to take a big step back, for a page or two, and look at XML (not to be
confused with XHTML). This is going to be a fast ride, so hang on...
Let’s use HTML for comparison. With HTML you’re basically told what elements you
can and can’t use, right? So, if you want to just make up an element, like , to
wrap around content, you can’t do it, can you? Ah, but with XML, you can. If fact, you
can invent totally new markup languages using XML. Let’s look at an example:
Here’s the root element. It’s not called , it’s called ,
since this is the XML for a recipe. Notice it has some extra attributes
in it, which you’ve never seen on an element in HTML.
Head First Lounge Iced Tea
A brisk iced tea with a bit of a kick. We
serve this all day long.
water
black tea
earl grey tea
ice
Boil one cup of water in a pan, remove pan, and
add tea. Let steep for five minutes.
Add ice to a pitcher, then add tea,
then 5 cups cold water.
Mix well and serve. Give tea a
quick shake in a shaker for an
extra touch.
Other than the element names, the way the
elements look and are used is just like HTML
(opening tags, closing tags, and so on).
moving to xhtml
Wow, look at these tags. The
s and s are all gone, and
instead we’ve got , ,
, s,
, and so on.
Just by looking at the
element names you can
tell this is a recipe.
This empty element looks
a little strange. We’ll come
back to that in a bit.
? brain
power
Think about how you would
create a Web page using HTML
to represent the recipe. How
would that be different from
using XML?
you are here 267