<s>
CKEditor	B-Application
(	O
formerly	O
known	O
as	O
FCKeditor	B-Application
)	O
is	O
a	O
WYSIWYG	B-Application
rich	B-Application
text	I-Application
editor	I-Application
which	O
enables	O
writing	O
content	O
directly	O
inside	O
of	O
web	O
pages	O
or	O
online	O
applications	O
.	O
</s>
<s>
Its	O
core	O
code	O
is	O
written	O
in	O
JavaScript	B-Language
and	O
it	O
is	O
developed	O
by	O
CKSource	O
.	O
</s>
<s>
CKEditor	B-Application
is	O
available	O
under	O
open	O
source	O
and	O
commercial	B-Application
licenses	O
.	O
</s>
<s>
The	O
first	O
version	O
of	O
CKEditor	B-Application
,	O
under	O
the	O
name	O
FCKeditor	B-Application
,	O
was	O
released	O
in	O
March	O
2003	O
by	O
Frederico	B-Application
Caldeira	I-Application
Knabben	I-Application
,	O
the	O
creator	O
of	O
the	O
editor	O
and	O
the	O
project	O
's	O
Benevolent	O
Dictator	O
for	O
Life	O
.	O
</s>
<s>
After	O
reaching	O
more	O
than	O
3	O
million	O
downloads	O
,	O
FCKeditor	B-Application
was	O
completely	O
reviewed	O
and	O
redesigned	O
into	O
CKEditor	B-Application
3	O
,	O
with	O
special	O
attention	O
given	O
to	O
performance	O
,	O
accessibility	O
and	O
a	O
new	O
UI	O
.	O
</s>
<s>
In	O
December	O
2012	O
,	O
CKEditor	B-Application
4	O
was	O
released	O
with	O
an	O
Inline	O
Editing	O
solution	O
,	O
reformatted	O
source	O
code	O
,	O
enhanced	O
DOM	O
and	O
CSS	B-Language
performance	O
.	O
</s>
<s>
After	O
five	O
years	O
,	O
in	O
2018	O
,	O
CKEditor	B-Application
5	O
first	O
stable	O
version	O
was	O
introduced	O
.	O
</s>
<s>
With	O
its	O
code	O
rewritten	O
from	O
scratch	O
,	O
CKEditor	B-Application
5	O
has	O
a	O
custom	O
data	O
model	O
and	O
architecture	O
.	O
</s>
<s>
The	O
editor	O
implements	O
Operational	B-Operating_System
Transformation	I-Operating_System
for	O
the	O
tree-structured	O
model	O
as	O
well	O
as	O
many	O
other	O
mechanisms	O
which	O
were	O
required	O
to	O
create	O
a	O
real-time	O
collaborative	O
UX	O
.	O
</s>
<s>
CKEditor	B-Application
5	O
is	O
a	O
JavaScript	B-Language
framework	O
offering	O
a	O
rich	O
API	O
to	O
develop	O
any	O
editing	O
solution	O
.	O
</s>
<s>
CKEditor	B-Application
5	O
also	O
offers	O
builds	O
,	O
which	O
are	O
ready-to-use	O
editors	O
;	O
there	O
are	O
currently	O
5	O
builds	O
available	O
to	O
download	O
:	O
Classic	O
,	O
Inline	O
,	O
Balloon	O
,	O
Balloon	O
block	O
and	O
Document	O
.	O
</s>
<s>
In	O
October	O
2017	O
,	O
CKSource	O
launched	O
the	O
CKEditor	B-Application
Ecosystem	O
.	O
</s>
<s>
CKEditor	B-Application
4	O
.	O
</s>
<s>
CKEditor	B-Application
5	O
Builds	O
and	O
CKEditor	B-Application
5	O
Framework	O
.	O
</s>
<s>
CKEditor	B-Application
Cloud	O
Services	O
,	O
a	O
cloud	O
platform	O
with	O
editing	O
features	O
and	O
real-time	O
collaboration	O
services	O
.	O
</s>
<s>
CKEditor	B-Application
4	O
has	O
features	O
found	O
in	O
desktop	B-Device
word	B-Application
processors	O
such	O
as	O
styles	O
formatting	O
(	O
bold	O
,	O
italic	O
,	O
underline	O
,	O
bulleted	O
and	O
numbered	O
lists	O
)	O
,	O
tables	O
,	O
block	O
quoting	O
,	O
web	O
resource	O
linking	O
,	O
safe	O
undo	O
function	O
,	O
image	O
inserting	O
,	O
paste	O
from	O
Word	B-Application
and	O
other	O
common	O
HTML	O
formatting	O
tools	O
.	O
</s>
<s>
Also	O
CKEditor	B-Application
4	O
has	O
built-in	O
spell	B-Application
checker	I-Application
functionality	O
provided	O
as	O
plug-ins	B-Application
by	O
LLC	O
.	O
</s>
<s>
There	O
are	O
currently	O
many	O
plugins	B-Application
available	O
with	O
CKEditor	B-Application
4	O
to	O
serve	O
different	O
needs	O
,	O
e.g.	O
</s>
<s>
CKFinder	O
and	O
Accessibility	O
Checker	O
(	O
the	O
CKSource	O
's	O
plugins	B-Application
)	O
.	O
</s>
<s>
It	O
is	O
compatible	O
with	O
both	O
CKEditor	B-Application
4	O
and	O
5	O
and	O
is	O
available	O
under	O
commercial	B-Application
license	O
.	O
</s>
<s>
Accessibility	O
Checker	O
is	O
available	O
under	O
both	O
Open	O
Source	O
and	O
commercial	B-Application
licenses	O
.	O
</s>
<s>
CKEditor	B-Application
5	O
's	O
architecture	O
and	O
custom	O
data	O
model	O
makes	O
it	O
possible	O
to	O
enable	O
real-time	B-Application
collaborative	I-Application
editing	I-Application
.	O
</s>
<s>
A	O
custom	O
collaborative	O
solution	O
can	O
be	O
built	O
by	O
using	O
the	O
CKEditor	B-Application
5	O
Framework	O
components	O
and	O
real-time	B-Application
collaborative	I-Application
editing	I-Application
can	O
be	O
enabled	O
by	O
connecting	O
to	O
the	O
CKEditor	B-Application
Cloud	O
Services	O
.	O
</s>
<s>
A	O
ready	O
to	O
use	O
,	O
drop-in	O
component	O
based	O
on	O
CKEditor	B-Application
5	O
(	O
Letters	O
)	O
offers	O
a	O
complete	O
solution	O
for	O
real-time	O
collaborative	O
writing	O
.	O
</s>
<s>
CKEditor	B-Application
4	O
is	O
fully	O
compatible	O
with	O
most	O
internet	O
browsers	O
,	O
including	O
latest	O
stable	O
releases	O
from	O
Google	B-Application
Chrome	I-Application
,	O
Firefox	B-Application
,	O
Safari	B-Application
,	O
Microsoft	B-Application
Edge	I-Application
,	O
Opera	B-Application
and	O
Internet	B-Application
Explorer	I-Application
10	O
and	O
11	O
.	O
</s>
<s>
In	O
mobile	O
environments	O
,	O
it	O
has	O
close	O
to	O
full	O
support	O
in	O
Safari	B-Application
(	O
iOS6	O
+	O
)	O
and	O
Chrome	B-Application
(	O
Android	O
)	O
.	O
</s>
<s>
CKEditor	B-Application
5	O
is	O
also	O
compatible	O
with	O
Google	B-Application
Chrome	I-Application
,	O
Firefox	B-Application
,	O
Safari	B-Application
,	O
Opera	B-Application
and	O
Microsoft	B-Application
Edge	I-Application
.	O
</s>
<s>
However	O
,	O
it	O
does	O
not	O
support	O
Internet	B-Application
Explorer	I-Application
11	O
yet	O
.	O
</s>
