<s>
In	O
computing	O
,	O
the	O
two	O
primary	O
stylesheet	B-Language
languages	I-Language
are	O
Cascading	B-Language
Style	I-Language
Sheets	I-Language
(	O
CSS	B-Language
)	O
and	O
the	O
Extensible	B-Language
Stylesheet	I-Language
Language	I-Language
(	O
XSL	B-Language
)	O
.	O
</s>
<s>
While	O
they	O
are	O
both	O
called	O
stylesheet	B-Language
languages	I-Language
,	O
they	O
have	O
very	O
different	O
purposes	O
and	O
ways	O
of	O
going	O
about	O
their	O
tasks	O
.	O
</s>
<s>
CSS	B-Language
is	O
designed	O
around	O
styling	O
a	O
document	O
,	O
structured	O
in	O
a	O
markup	O
language	O
,	O
HTML	B-Language
and	O
XML	B-Protocol
(	O
including	O
XHTML	B-Language
and	O
SVG	B-Application
)	O
documents	O
.	O
</s>
<s>
The	O
code	O
CSS	B-Language
is	O
non-XML	O
syntax	O
to	O
define	O
the	O
style	O
information	O
for	O
the	O
various	O
elements	O
of	O
the	O
document	O
that	O
it	O
styles	O
.	O
</s>
<s>
The	O
language	O
to	O
structure	O
a	O
document	O
(	O
markup	O
language	O
)	O
is	O
a	O
prelimit	O
to	O
CSS	B-Language
.	O
</s>
<s>
A	O
markup	O
language	O
,	O
like	O
HTML	B-Language
and	O
less	O
XUL	O
,	O
may	O
define	O
some	O
primitive	O
elements	O
to	O
style	O
a	O
document	O
,	O
for	O
example	O
<emphasis>	O
to	O
bold	O
.	O
</s>
<s>
CSS	B-Language
post	O
styles	O
a	O
document	O
to	O
"	O
screen	O
media	O
"	O
or	O
"	O
paged	O
media	O
"	O
.	O
</s>
<s>
Since	O
CSS	B-Language
was	O
designed	O
originally	O
for	O
screen	O
media	O
,	O
its	O
paged	O
facilities	O
lacked	O
.	O
</s>
<s>
CSS	B-Language
version	O
3.0	O
provides	O
new	O
features	O
that	O
allow	O
CSS	B-Language
to	O
more	O
adequately	O
style	O
documents	O
for	O
paged	O
display	O
.	O
</s>
<s>
XSL	B-Language
has	O
evolved	O
drastically	O
from	O
its	O
initial	O
design	O
into	O
something	O
very	O
different	O
from	O
its	O
original	O
purpose	O
.	O
</s>
<s>
The	O
original	O
idea	O
for	O
XSL	B-Language
was	O
to	O
create	O
an	O
XML-based	O
styling	O
language	O
directed	O
toward	O
paged	O
display	O
media	O
.	O
</s>
<s>
First	O
,	O
the	O
XML	B-Protocol
document	I-Protocol
would	O
be	O
transformed	O
into	O
an	O
intermediate	O
form	O
.	O
</s>
<s>
The	O
process	O
for	O
performing	O
this	O
transformation	O
would	O
be	O
governed	O
by	O
the	O
XSL	B-Language
stylesheet	I-Language
,	O
as	O
defined	O
by	O
the	O
XSL	B-Language
specification	O
.	O
</s>
<s>
The	O
result	O
of	O
this	O
transformation	O
would	O
be	O
an	O
XML	B-Protocol
document	I-Protocol
in	O
an	O
intermediate	O
language	O
,	O
known	O
as	O
XSL-FO	B-Language
(	O
also	O
defined	O
by	O
the	O
XSL	B-Language
specification	O
)	O
.	O
</s>
<s>
However	O
,	O
in	O
the	O
process	O
of	O
designing	O
the	O
transformation	O
step	O
,	O
it	O
was	O
realized	O
that	O
a	O
generic	O
XML	B-Protocol
transformation	O
language	O
would	O
be	O
useful	O
for	O
more	O
than	O
merely	O
creating	O
a	O
presentation	O
of	O
an	O
XML	B-Protocol
document	I-Protocol
.	O
</s>
<s>
As	O
such	O
,	O
a	O
new	O
working	O
group	O
was	O
split	O
off	O
from	O
the	O
XSL	B-Language
working	O
group	O
,	O
and	O
the	O
XSL	B-Application
Transformations	I-Application
(	O
XSLT	B-Application
)	O
language	O
became	O
something	O
that	O
was	O
considered	O
separate	O
from	O
the	O
styling	O
information	O
of	O
the	O
XSL-FO	B-Language
document	O
.	O
</s>
<s>
Even	O
that	O
split	O
was	O
expanded	O
when	O
XPath	B-Language
became	O
its	O
own	O
separate	O
specification	O
,	O
though	O
still	O
strongly	O
tied	O
to	O
XSLT	B-Application
.	O
</s>
<s>
The	O
combination	O
of	O
XSLT	B-Application
and	O
XSL-FO	B-Language
creates	O
a	O
powerful	O
styling	O
language	O
,	O
though	O
much	O
more	O
complex	O
than	O
CSS	B-Language
.	O
</s>
<s>
XSLT	B-Application
is	O
a	O
Turing	B-Algorithm
complete	I-Algorithm
language	O
,	O
while	O
CSS	B-Language
is	O
not	O
;	O
this	O
demonstrates	O
a	O
degree	O
of	O
power	O
and	O
flexibility	O
not	O
found	O
in	O
CSS	B-Language
.	O
</s>
<s>
Additionally	O
,	O
XSLT	B-Application
is	O
capable	O
of	O
creating	O
content	O
,	O
such	O
as	O
automatically	O
creating	O
a	O
table	O
of	O
contents	O
just	O
from	O
chapters	O
in	O
a	O
book	O
,	O
or	O
removing/selecting	O
content	O
,	O
such	O
as	O
only	O
generating	O
a	O
glossary	O
from	O
a	O
book	O
.	O
</s>
<s>
XSLT	B-Application
version	O
1.0	O
with	O
the	O
EXSLT	B-Language
extensions	O
,	O
or	O
XSLT	B-Application
version	O
2.0	O
is	O
capable	O
of	O
generating	O
multiple	O
documents	O
as	O
well	O
,	O
such	O
as	O
dividing	O
the	O
chapters	O
in	O
a	O
book	O
into	O
their	O
own	O
individual	O
pages	O
.	O
</s>
<s>
By	O
contrast	O
,	O
a	O
CSS	B-Language
can	O
only	O
selectively	O
remove	O
content	O
by	O
not	O
displaying	O
it	O
.	O
</s>
<s>
XSL-FO	B-Language
is	O
unlike	O
CSS	B-Language
in	O
that	O
the	O
XSL-FO	B-Language
document	O
stands	O
alone	O
.	O
</s>
<s>
CSS	B-Language
modifies	O
a	O
document	O
that	O
is	O
attached	O
to	O
it	O
,	O
while	O
the	O
XSL-FO	B-Language
document	O
(	O
usually	O
the	O
result	O
of	O
the	O
transformation	O
by	O
XSLT	B-Application
of	O
the	O
original	O
document	O
)	O
contains	O
all	O
of	O
the	O
content	O
to	O
be	O
presented	O
in	O
a	O
purely	O
presentational	O
format	O
.	O
</s>
<s>
The	O
XSL-FO	B-Language
document	O
must	O
be	O
passed	O
through	O
an	O
XSL-FO	B-Language
processor	O
utility	O
that	O
generates	O
the	O
final	O
paged	O
media	O
,	O
much	O
like	O
HTML+CSS	O
must	O
pass	O
through	O
a	O
web	B-Application
browser	I-Application
to	O
be	O
displayed	O
in	O
its	O
formatted	O
state	O
.	O
</s>
<s>
The	O
complexity	O
of	O
XSL-FO	B-Language
is	O
a	O
problem	O
,	O
largely	O
because	O
implementing	O
an	O
FO	O
processor	O
is	O
very	O
difficult	O
.	O
</s>
<s>
CSS	B-Language
implementations	O
in	O
web	B-Application
browsers	I-Application
are	O
still	O
not	O
entirely	O
compatible	O
with	O
one	O
another	O
,	O
and	O
it	O
is	O
much	O
simpler	O
to	O
write	O
a	O
CSS	B-Language
processor	O
than	O
an	O
FO	O
processor	O
.	O
</s>
