<s>
An	O
XML	B-Protocol
editor	I-Protocol
is	O
a	O
markup	O
language	O
editor	B-Application
with	O
added	O
functionality	O
to	O
facilitate	O
the	O
editing	O
of	O
XML	B-Protocol
.	O
</s>
<s>
This	O
can	O
be	O
done	O
using	O
a	O
plain	O
text	B-Application
editor	I-Application
,	O
with	O
all	O
the	O
code	O
visible	O
,	O
but	O
XML	B-Protocol
editors	I-Protocol
have	O
added	O
facilities	O
like	O
tag	O
completion	O
and	O
menus	O
and	O
buttons	O
for	O
tasks	O
that	O
are	O
common	O
in	O
XML	B-Protocol
editing	O
,	O
based	O
on	O
data	O
supplied	O
with	O
document	B-Language
type	I-Language
definition	I-Language
(	O
DTD	O
)	O
or	O
the	O
XML	B-Protocol
tree	O
.	O
</s>
<s>
There	O
are	O
also	O
graphical	B-Application
XML	I-Application
editors	I-Application
that	O
hide	O
the	O
code	O
in	O
the	O
background	O
and	O
present	O
the	O
content	O
to	O
the	O
user	O
in	O
a	O
more	O
user-friendly	O
format	O
,	O
approximating	O
the	O
rendered	O
version	O
or	O
editing	O
forms	O
.	O
</s>
<s>
This	O
is	O
helpful	O
for	O
situations	O
where	O
people	O
who	O
are	O
not	O
fluent	O
in	O
XML	B-Protocol
code	O
need	O
to	O
enter	O
information	O
in	O
XML	B-Protocol
based	O
documents	O
such	O
as	O
time	O
sheets	O
and	O
expenditure	O
reports	O
.	O
</s>
<s>
And	O
even	O
if	O
the	O
user	O
is	O
familiar	O
with	O
XML	B-Protocol
,	O
use	O
of	O
such	O
editors	O
,	O
which	O
take	O
care	O
of	O
syntax	O
details	O
,	O
is	O
often	O
faster	O
and	O
more	O
convenient	O
.	O
</s>
<s>
An	O
XML	B-Protocol
editor	I-Protocol
goes	O
beyond	O
the	O
syntax	O
highlighting	O
offered	O
by	O
many	O
plaintext	B-Application
editors	I-Application
and	O
generic	O
source	B-Application
code	I-Application
editors	I-Application
,	O
verifying	O
the	O
XML	B-Protocol
source	O
based	O
on	O
an	O
XML	B-Language
schema	I-Language
or	O
XML	B-Language
DTD	I-Language
,	O
and	O
some	O
can	O
do	O
it	O
as	O
the	O
document	O
is	O
being	O
edited	O
in	O
real	O
time	O
.	O
</s>
<s>
Other	O
features	O
of	O
an	O
editor	B-Application
designed	O
specifically	O
for	O
editing	O
XML	B-Protocol
might	O
include	O
element	O
word	O
completion	O
and	O
automatic	O
appending	O
of	O
a	O
closing	O
tag	O
whenever	O
an	O
opening	O
tag	O
is	O
entered	O
.	O
</s>
<s>
These	O
features	O
can	O
help	O
to	O
prevent	O
typographically	O
originating	O
errors	O
in	O
the	O
XML	B-Protocol
code	O
.	O
</s>
<s>
Some	O
XML	B-Protocol
editors	I-Protocol
provide	O
for	O
the	O
ability	O
to	O
run	O
an	O
XSLT	B-Application
transform	O
,	O
or	O
series	O
of	O
transforms	O
,	O
over	O
a	O
document	O
.	O
</s>
<s>
Some	O
of	O
the	O
larger	O
XML	B-Protocol
packages	O
even	O
offer	O
XSLT	B-Application
debugging	O
features	O
and	O
XSL-FO	B-Language
processors	O
for	O
generation	O
of	O
PDF	B-Application
files	I-Application
from	O
documents	O
.	O
</s>
<s>
Graphical	O
editors	O
based	O
on	O
GUIs	O
may	O
be	O
easier	O
for	O
some	O
people	O
to	O
use	O
than	O
text	B-Application
editors	I-Application
,	O
and	O
may	O
not	O
require	O
knowledge	O
of	O
XML	B-Protocol
syntax	O
.	O
</s>
<s>
These	O
are	O
often	O
called	O
WYSIWYG	B-Application
(	O
"	O
What	B-Application
You	I-Application
See	I-Application
Is	I-Application
What	I-Application
You	I-Application
Get	I-Application
"	O
)	O
editors	O
,	O
but	O
not	O
all	O
of	O
them	O
are	O
WYSIWYG	B-Application
:	O
graphical	B-Application
XML	I-Application
editors	I-Application
can	O
be	O
WYSIWYG	B-Application
when	O
they	O
try	O
to	O
display	O
the	O
final	O
rendering	O
or	O
WYSIWYM	B-General_Concept
(	O
"	O
What	O
You	O
See	O
Is	O
What	O
You	O
Mean	O
"	O
)	O
when	O
they	O
try	O
to	O
display	O
the	O
actual	O
meaning	O
of	O
XML	B-Protocol
elements	O
.	O
</s>
<s>
When	O
they	O
are	O
not	O
WYSIWYG	B-Application
,	O
they	O
do	O
not	O
display	O
the	O
(	O
or	O
one	O
of	O
the	O
)	O
graphical	O
end	O
result	O
of	O
a	O
document	O
,	O
but	O
instead	O
focus	O
on	O
conveying	O
the	O
meaning	O
of	O
the	O
text	O
.	O
</s>
<s>
They	O
use	O
DTDs	O
or	O
XML	B-Language
schemas	I-Language
and/or	O
configuration	O
files	O
to	O
map	O
XML	B-Protocol
elements	O
to	O
graphical	O
components	O
.	O
</s>
<s>
These	O
kinds	O
of	O
editors	O
are	O
generally	O
more	O
useful	O
for	O
XML	B-Protocol
languages	O
for	O
data	O
rather	O
than	O
for	O
storing	O
documents	O
.	O
</s>
<s>
In	O
the	O
above	O
example	O
,	O
the	O
editor	B-Application
is	O
using	O
a	O
configuration	O
file	O
to	O
know	O
that	O
the	O
TABLE	O
element	O
represents	O
a	O
table	O
,	O
the	O
TR	O
element	O
represents	O
a	O
row	O
of	O
the	O
table	O
,	O
and	O
the	O
TD	O
element	O
represents	O
a	O
cell	O
of	O
the	O
table	O
.	O
</s>
<s>
For	O
instance	O
,	O
in	O
a	O
text	B-Application
editor	I-Application
,	O
it	O
is	O
possible	O
to	O
create	O
a	O
row	O
with	O
too	O
many	O
cells	O
in	O
the	O
table	O
,	O
while	O
this	O
would	O
not	O
be	O
possible	O
with	O
the	O
above	O
graphical	O
user	O
interface	O
.	O
</s>
<s>
WYSIWYG	B-Application
editors	I-Application
let	O
people	O
edit	O
files	O
directly	O
with	O
the	O
tags	O
represented	O
by	O
some	O
form	O
of	O
graphical	O
viewing	O
rather	O
than	O
bare	O
XML	B-Protocol
code	O
.	O
</s>
<s>
Often	O
,	O
WYSIWYG	B-Application
editors	I-Application
attempt	O
to	O
emulate	O
the	O
end	O
result	O
of	O
some	O
transform	O
or	O
CSS	B-Language
stylesheet	I-Language
application	O
.	O
</s>
<s>
This	O
emulation	O
may	O
or	O
may	O
not	O
be	O
possible	O
,	O
depending	O
on	O
the	O
transformation	O
from	O
XML	B-Protocol
into	O
the	O
end	O
result	O
.	O
</s>
<s>
Naive	O
use	O
of	O
a	O
WYSIWYG	B-Application
editor	I-Application
can	O
lead	O
to	O
the	O
creation	O
of	O
documents	O
that	O
do	O
not	O
have	O
the	O
intrinsic	O
semantics	O
of	O
the	O
particular	O
XML	B-Protocol
language	O
.	O
</s>
<s>
This	O
comes	O
about	O
if	O
the	O
user	O
is	O
focused	O
on	O
trying	O
to	O
achieve	O
a	O
certain	O
visual	O
presentation	O
with	O
the	O
editor	B-Application
,	O
rather	O
than	O
using	O
the	O
WYSIWYG	B-Application
to	O
make	O
editing	O
the	O
document	O
easier	O
.	O
</s>
<s>
For	O
instance	O
,	O
someone	O
creating	O
a	O
web	O
page	O
could	O
use	O
an	O
H2	O
element	O
(	O
meaning	O
:	O
second	O
level	O
title	O
)	O
instead	O
of	O
H1	O
(	O
meaning	O
:	O
first	O
level	O
title	O
)	O
because	O
it	O
looks	O
smaller	O
on	O
their	O
current	O
WYSIWYG	B-Application
editor	I-Application
.	O
</s>
<s>
Such	O
an	O
author	O
is	O
making	O
a	O
choice	O
based	O
on	O
the	O
apparent	O
visual	O
representation	O
,	O
but	O
a	O
visitor	O
to	O
the	O
author	O
's	O
web	O
page	O
can	O
offer	O
a	O
very	O
different	O
rendering	O
in	O
their	O
browser	B-Application
.	O
</s>
<s>
However	O
,	O
as	O
long	O
as	O
the	O
underlying	O
meaning	O
of	O
the	O
document	O
is	O
understood	O
by	O
the	O
author	O
,	O
and	O
the	O
author	O
does	O
not	O
make	O
decisions	O
based	O
on	O
the	O
exact	O
look	O
in	O
the	O
WYSIWYG	B-Application
editor	I-Application
,	O
such	O
an	O
editor	B-Application
can	O
be	O
of	O
value	O
to	O
the	O
writer	O
.	O
</s>
<s>
It	O
is	O
generally	O
much	O
easier	O
to	O
read	O
a	O
document	O
that	O
is	O
being	O
rendered	O
in	O
some	O
fashion	O
than	O
it	O
is	O
to	O
read	O
the	O
raw	O
XML	B-Protocol
code	O
.	O
</s>
<s>
Also	O
,	O
editing	O
can	O
be	O
much	O
more	O
intuitive	O
,	O
as	O
the	O
WYSIWYG	B-Application
editor	I-Application
can	O
use	O
tools	O
similar	O
to	O
many	O
word	O
processing	O
applications	O
.	O
</s>
<s>
Some	O
WYSIWYG	B-Application
editors	I-Application
even	O
allow	O
the	O
user	O
to	O
use	O
a	O
DTD	O
or	O
Schema	O
and	O
define	O
their	O
own	O
user	O
interface	O
for	O
editing	O
.	O
</s>
<s>
Usually	O
WYSIWYG	B-Application
editors	I-Application
support	O
CSS	B-Language
but	O
not	O
XSLT	B-Application
,	O
because	O
XSLT	B-Application
transformations	O
can	O
be	O
very	O
complex	O
,	O
and	O
guessing	O
what	O
the	O
user	O
meant	O
when	O
changing	O
the	O
end	O
result	O
can	O
be	O
impossible	O
.	O
</s>
<s>
The	O
WYSIWYG	B-Application
editors	I-Application
that	O
do	O
support	O
XSLT	B-Application
,	O
such	O
as	O
Syntext	O
Serna	O
,	O
will	O
therefore	O
apply	O
changes	O
directly	O
to	O
the	O
original	O
XML	B-Protocol
,	O
while	O
updating	O
the	O
view	O
by	O
running	O
the	O
XSLT	B-Application
for	O
every	O
change	O
.	O
</s>
