<s>
Netscape	B-Protocol
Plugin	I-Protocol
Application	I-Protocol
Programming	I-Protocol
Interface	I-Protocol
(	O
NPAPI	B-Protocol
)	O
was	O
an	O
application	B-Application
programming	I-Application
interface	I-Application
(	O
API	B-Application
)	O
of	O
the	O
web	B-Application
browsers	I-Application
that	O
allows	O
plugins	B-Application
to	O
be	O
integrated	O
.	O
</s>
<s>
Initially	O
developed	O
for	O
Netscape	B-Protocol
browsers	B-Application
,	O
starting	O
in	O
1995	O
with	O
Netscape	B-Protocol
Navigator	I-Protocol
2.0	O
,	O
it	O
was	O
subsequently	O
adopted	O
by	O
other	O
browsers	B-Application
.	O
</s>
<s>
In	O
NPAPI	B-Protocol
architecture	O
,	O
a	O
plugin	B-Application
declares	O
content	B-Application
types	I-Application
(	O
e.g.	O
</s>
<s>
When	O
the	O
browser	B-Application
encounters	O
a	O
content	B-Application
type	I-Application
it	O
cannot	O
handle	O
natively	O
,	O
it	O
loads	O
the	O
appropriate	O
plugin	B-Application
,	O
sets	O
aside	O
space	O
within	O
the	O
browser	B-Application
context	O
for	O
the	O
plugin	B-Application
to	O
render	O
and	O
then	O
streams	O
data	O
to	O
it	O
.	O
</s>
<s>
The	O
plugin	B-Application
is	O
responsible	O
for	O
rendering	O
the	O
data	O
.	O
</s>
<s>
The	O
plugin	B-Application
runs	O
in-place	O
within	O
the	O
page	O
,	O
as	O
opposed	O
to	O
older	O
browsers	B-Application
that	O
had	O
to	O
launch	O
an	O
external	O
application	O
to	O
handle	O
unknown	O
content	B-Application
types	I-Application
.	O
</s>
<s>
NPAPI	B-Protocol
requires	O
each	O
plugin	B-Application
to	O
implement	O
and	O
expose	O
approximately	O
15	O
functions	O
for	O
initializing	O
,	O
creating	O
,	O
deleting	O
and	O
positioning	O
plugin	B-Application
content	O
.	O
</s>
<s>
NPAPI	B-Protocol
also	O
supports	O
scripting	O
,	O
printing	O
,	O
full-screen	O
plugins	B-Application
,	O
windowless	O
plugins	B-Application
and	O
content	O
streaming	O
.	O
</s>
<s>
NPAPI	B-Protocol
was	O
frequently	O
used	O
for	O
plugins	B-Application
which	O
required	O
intensive	O
,	O
low-level	O
performance	O
such	O
as	O
video	O
players	O
,	O
including	O
Adobe	B-Operating_System
Flash	I-Operating_System
Player	I-Operating_System
and	O
Microsoft	B-Application
Silverlight	I-Application
,	O
as	O
well	O
as	O
platforms	O
for	O
web	O
applications	O
such	O
as	O
the	O
Java	B-Language
Runtime	O
Environment	O
.	O
</s>
<s>
NPAPI	B-Protocol
support	O
among	O
major	O
browsers	B-Application
started	O
to	O
wane	O
since	O
2015	O
and	O
it	O
was	O
gradually	O
deprecated	O
over	O
the	O
following	O
7	O
years	O
.	O
</s>
<s>
With	O
the	O
advent	O
of	O
HTML5	B-Application
,	O
all	O
major	O
web	B-Application
browsers	I-Application
have	O
removed	O
support	O
for	O
3rd	O
party	O
NPAPI	B-Protocol
plugins	B-Application
for	O
security	O
reasons	O
.	O
</s>
<s>
Scripting	O
is	O
a	O
feature	O
allowing	O
JavaScript	B-Language
code	O
in	O
a	O
web	O
page	O
to	O
interact	O
with	O
the	O
plugin	B-Application
.	O
</s>
<s>
Various	O
versions	O
of	O
Netscape	B-Protocol
and	O
then	O
Mozilla	B-Language
supported	O
this	O
feature	O
using	O
different	O
technologies	O
,	O
including	O
LiveConnect	O
,	O
XPConnect	O
,	O
and	O
NPRuntime	O
.	O
</s>
<s>
LiveConnect	O
is	O
a	O
feature	O
of	O
Web	B-Application
browsers	I-Application
that	O
allows	O
Java	B-Language
and	O
JavaScript	B-Language
software	O
to	O
intercommunicate	O
within	O
a	O
Web	O
page	O
.	O
</s>
<s>
From	O
the	O
Java	B-Language
side	O
it	O
allows	O
an	O
applet	O
to	O
invoke	O
the	O
embedded	O
scripts	O
of	O
a	O
page	O
,	O
or	O
to	O
access	O
the	O
built-in	O
JavaScript	B-Language
environment	O
,	O
much	O
as	O
scripts	O
can	O
.	O
</s>
<s>
Conversely	O
,	O
from	O
the	O
JavaScript	B-Language
side	O
,	O
it	O
allows	O
a	O
script	O
to	O
invoke	O
applet	O
methods	B-Language
,	O
or	O
to	O
access	O
Java	B-Language
runtime	O
libraries	O
,	O
much	O
as	O
applets	O
can	O
.	O
</s>
<s>
LiveConnect	O
was	O
used	O
in	O
Netscape	B-Protocol
4	I-Protocol
to	O
implement	O
scriptability	O
of	O
NPAPI	B-Protocol
plugins	B-Application
.	O
</s>
<s>
The	O
Open	O
Java	B-Language
Interface-dependent	O
implementation	O
of	O
LiveConnect	O
was	O
removed	O
from	O
the	O
Mozilla	B-Language
source	O
code	O
tree	O
in	O
late	O
June	O
2009	O
as	O
part	O
of	O
the	O
cleanup	O
effort	O
.	O
</s>
<s>
It	O
is	O
no	O
longer	O
needed	O
with	O
the	O
release	O
of	O
a	O
redesigned	O
Java	B-Language
Runtime	O
Environment	O
from	O
Sun	O
Microsystems	O
.	O
</s>
<s>
However	O
the	O
old	O
implementation	O
was	O
restored	O
for	O
Gecko	O
1.9.2	O
,	O
as	O
Apple	O
had	O
yet	O
to	O
port	O
the	O
newer	O
JRE	O
over	O
to	O
Mac	B-Application
OS	I-Application
X	O
.	O
</s>
<s>
The	O
Java	B-Language
–	O
JavaScript	B-Language
functionality	O
supported	O
by	O
the	O
redesigned	O
Java	B-Language
Runtime	O
Environment	O
is	O
still	O
called	O
"	O
LiveConnect	O
"	O
,	O
despite	O
the	O
Open	O
Java	B-Language
Interface-specific	O
approach	O
having	O
been	O
abandoned	O
.	O
</s>
<s>
With	O
Netscape	B-Protocol
4	I-Protocol
,	O
NPAPI	B-Protocol
was	O
extended	O
to	O
allow	O
plugins	B-Application
to	O
be	O
scripted	O
.	O
</s>
<s>
A	O
plugin	B-Application
could	O
implement	O
a	O
Java	B-Language
class	O
and	O
expose	O
an	O
instance	O
of	O
it	O
.	O
</s>
<s>
The	O
class	O
could	O
be	O
called	O
from	O
JavaScript	B-Language
and	O
from	O
Java	B-Application
applets	I-Application
running	O
within	O
the	O
page	O
.	O
</s>
<s>
The	O
disadvantage	O
of	O
LiveConnect	O
is	O
,	O
that	O
it	O
is	O
heavily	O
tied	O
to	O
the	O
version	O
of	O
Java	B-Language
embedded	O
within	O
the	O
Netscape	B-Protocol
browser	B-Application
.	O
</s>
<s>
This	O
prevented	O
the	O
browser	B-Application
from	O
using	O
other	O
Java	B-Language
runtimes	O
,	O
and	O
added	O
bloat	O
to	O
the	O
browser	B-Application
download	O
size	O
,	O
since	O
it	O
required	O
Java	B-Language
to	O
script	O
plugins	B-Application
.	O
</s>
<s>
Additionally	O
,	O
LiveConnect	O
is	O
tricky	O
to	O
program	O
:	O
The	O
developer	O
has	O
to	O
define	O
a	O
Java	B-Language
class	O
for	O
the	O
plugin	B-Application
,	O
run	O
it	O
through	O
a	O
specialized	O
Java	B-Language
header	B-Language
compiler	B-Language
,	O
and	O
implement	O
native	B-Language
methods	I-Language
.	O
</s>
<s>
Handling	O
strings	O
,	O
exceptions	B-General_Concept
,	O
and	O
other	O
Java	B-Language
objects	B-Language
from	O
C++	B-Language
is	O
non-obvious	O
.	O
</s>
<s>
In	O
addition	O
,	O
LiveConnect	O
uses	O
an	O
earlier	O
and	O
now	O
obsolete	O
application	B-Application
programming	I-Application
interface	I-Application
(	O
API	B-Application
)	O
for	O
invoking	O
native	O
C++	B-Language
calls	O
from	O
Java	B-Language
,	O
called	O
JRI	O
.	O
</s>
<s>
The	O
JRI	O
technology	O
has	O
long	O
since	O
been	O
supplanted	O
by	O
JNI	B-Language
.	O
</s>
<s>
XPConnect	O
(	O
Cross	O
Platform	O
Connect	O
)	O
is	O
a	O
technology	O
which	O
enables	O
simple	O
interoperation	O
between	O
XPCOM	B-Application
and	O
JavaScript	B-Language
.	O
</s>
<s>
XPConnect	O
allows	O
JavaScript	B-Language
objects	B-Language
to	O
transparently	O
access	O
and	O
manipulate	O
XPCOM	B-Application
objects	B-Language
.	O
</s>
<s>
It	O
also	O
enables	O
JavaScript	B-Language
objects	B-Language
to	O
present	O
XPCOM	B-Application
compliant	O
interfaces	B-Application
to	O
be	O
called	O
by	O
XPCOM	B-Application
objects	B-Language
.	O
</s>
<s>
A	O
main	O
goal	O
is	O
that	O
objects	B-Language
communicating	O
from	O
either	O
side	O
of	O
an	O
XPCOM	B-Application
style	O
interface	O
should	O
not	O
generally	O
need	O
to	O
know	O
or	O
care	O
about	O
the	O
implementation	O
language	O
of	O
the	O
object	O
on	O
the	O
other	O
side	O
of	O
the	O
interface	O
.	O
</s>
<s>
XPConnect	O
's	O
primary	O
reason	O
for	O
existence	O
is	O
to	O
replace	O
handwritten	O
code	O
used	O
in	O
places	O
where	O
native	O
code	O
needs	O
to	O
interact	O
with	O
JavaScript	B-Language
code	O
.	O
</s>
<s>
An	O
example	O
is	O
the	B-General_Concept
DOM	I-General_Concept
module	O
.	O
</s>
<s>
Full	O
privileges	O
are	O
only	O
granted	O
by	O
default	O
to	O
chrome	B-Application
scripts	O
,	O
i.e.	O
</s>
<s>
For	O
remote	O
HTML/XHTML/XUL	O
documents	O
,	O
most	O
XPCOM	B-Application
objects	B-Language
are	O
not	O
accessible	O
by	O
the	O
scripts	O
as	O
they	O
have	O
limited	O
privileges	O
due	O
to	O
security	O
reasons	O
.	O
</s>
<s>
the	O
XMLHttpRequest	B-Protocol
object	O
)	O
,	O
the	O
usual	O
security	O
restrictions	O
can	O
also	O
be	O
found	O
(	O
e.g.	O
</s>
<s>
Mozilla	B-Language
was	O
already	O
using	O
XPCOM	B-Application
to	O
define	O
the	O
interfaces	B-Application
to	O
many	O
objects	B-Language
implemented	O
in	O
C++	B-Language
.	O
</s>
<s>
Each	O
interface	O
was	O
defined	O
by	O
an	O
IDL	B-General_Concept
file	O
,	O
and	O
run	O
through	O
an	O
IDL	B-General_Concept
compiler	B-Language
that	O
produced	O
header	B-Language
files	I-Language
and	O
a	O
language-neutral	O
type	O
library	O
that	O
was	O
a	O
binary	O
representation	O
of	O
the	O
interface	O
.	O
</s>
<s>
This	O
binary	O
described	O
the	O
interface	O
,	O
the	O
methods	B-Language
,	O
the	O
parameters	O
,	O
the	O
data	O
structures	O
and	O
enumerations	B-Language
.	O
</s>
<s>
XPConnect	O
uses	O
the	O
type	O
library	O
information	O
to	O
marshal	O
calls	O
between	O
different	O
thread	O
contexts	O
and	O
between	O
JavaScript	B-Language
and	O
natively	O
compiled	B-Language
C++	B-Language
.	O
</s>
<s>
XPConnect	O
is	O
used	O
extensively	O
throughout	O
Mozilla	B-Language
.	O
</s>
<s>
Starting	O
with	O
Netscape	B-Protocol
6.1	O
and	O
Mozilla	B-Language
0.9.2	O
,	O
NPAPI	B-Protocol
was	O
extended	O
,	O
so	O
that	O
a	O
plugin	B-Application
could	O
return	O
a	O
scriptable	O
interface	O
to	O
itself	O
and	O
XPConnect	O
would	O
marshal	O
calls	O
to	O
it	O
from	O
JavaScript	B-Language
and	O
the	O
C++	B-Language
implementation	O
.	O
</s>
<s>
XPConnect	O
has	O
no	O
Java	B-Language
dependency	O
.	O
</s>
<s>
However	O
,	O
the	O
technology	O
is	O
based	O
on	O
XPCOM	B-Application
.	O
</s>
<s>
Thus	O
the	O
plugin	B-Application
developer	O
must	O
be	O
familiar	O
with	O
reference	B-General_Concept
counting	I-General_Concept
,	O
interfaces	B-Application
and	O
IDL	B-General_Concept
to	O
implement	O
scripting	O
.	O
</s>
<s>
The	O
dependency	O
on	O
XPCOM	B-Application
led	O
to	O
certain	O
dynamic	O
linking	O
issues	O
(	O
e.g.	O
</s>
<s>
the	O
fragile	B-Application
base	I-Application
class	I-Application
problem	I-Application
)	O
which	O
had	O
to	O
be	O
solved	O
before	O
the	O
plugin	B-Application
would	O
work	O
correctly	O
with	O
different	O
browsers	B-Application
.	O
</s>
<s>
XPCOM	B-Application
has	O
since	O
been	O
changed	O
to	O
supply	O
a	O
statically	O
linked	O
version	O
to	O
address	O
such	O
issues	O
.	O
</s>
<s>
This	O
approach	O
also	O
requires	O
an	O
.xpt	O
file	O
to	O
be	O
installed	O
next	O
to	O
the	O
dynamic-link	O
library	O
(	O
DLL	O
)	O
;	O
otherwise	O
the	O
plugin	B-Application
appears	O
to	O
work	O
,	O
but	O
the	O
scripting	O
does	O
not	O
,	O
causing	O
confusion	O
.	O
</s>
<s>
At	O
the	O
end	O
of	O
2004	O
,	O
all	O
major	O
browser	B-Application
companies	O
using	O
NPAPI	B-Protocol
agreed	O
on	O
NPRuntime	O
as	O
an	O
extension	O
to	O
the	O
original	O
NPAPI	B-Protocol
to	O
supply	O
scripting	O
,	O
via	O
an	O
API	B-Application
that	O
is	O
similar	O
in	O
style	O
to	O
the	O
old	O
C-style	O
NPAPI	B-Protocol
and	O
is	O
independent	O
of	O
other	O
browser	B-Application
technologies	O
like	O
Java	B-Language
or	O
XPCOM	B-Application
.	O
</s>
<s>
It	O
is	O
only	O
supported	O
by	O
Firefox	B-Application
ESR	O
(	O
Extended	O
Support	O
Release	O
)	O
and	O
Safari	B-Application
.	O
</s>
<s>
Because	O
of	O
the	O
age	O
of	O
the	O
API	B-Application
,	O
security	O
issues	O
,	O
and	O
adoption	O
of	O
alternative	O
technologies	O
such	O
as	O
HTML5	B-Application
,	O
many	O
software	O
vendors	O
began	O
to	O
phase	O
out	O
NPAPI	B-Protocol
support	O
in	O
2013	O
.	O
</s>
<s>
Internet	B-Application
Explorer	I-Application
versions	O
3	O
through	O
5.5	O
SP2	O
supported	O
NPAPI	B-Protocol
,	O
allowing	O
plugins	B-Application
that	O
functioned	O
in	O
Netscape	B-Protocol
Navigator	I-Protocol
to	O
function	O
in	O
Internet	B-Application
Explorer	I-Application
.	O
</s>
<s>
Support	O
came	O
via	O
a	O
small	O
ActiveX	B-Application
control	I-Application
(	O
named	O
"	O
plugin.ocx	O
"	O
)	O
that	O
acted	O
as	O
a	O
shim	B-General_Concept
between	O
ActiveX	B-Application
and	O
the	O
NPAPI	B-Protocol
plugin	B-Application
.	O
</s>
<s>
Google	B-Application
Chrome	I-Application
permanently	O
dropped	O
all	O
NPAPI	B-Protocol
support	O
from	O
all	O
platforms	O
in	O
September	O
2015	O
.	O
</s>
<s>
In	O
September	O
2013	O
,	O
Google	O
announced	O
that	O
it	O
would	O
phase	O
out	O
NPAPI	B-Protocol
support	O
in	O
its	O
Google	B-Application
Chrome	I-Application
browser	I-Application
during	O
2014	O
,	O
stating	O
that	O
"[its]	O
90s-era	O
architecture	O
has	O
become	O
a	O
leading	O
cause	O
of	O
hangs	O
,	O
crashes	O
,	O
security	O
incidents	O
,	O
and	O
code	O
complexity	O
"	O
.	O
</s>
<s>
In	O
May	O
2014	O
,	O
NPAPI	B-Protocol
support	O
was	O
removed	O
from	O
the	O
Linux	B-Application
version	O
of	O
Chrome	B-Application
35	O
and	O
later	O
.	O
</s>
<s>
In	O
April	O
2015	O
,	O
Chrome	B-Application
for	O
Windows	O
and	O
OS	B-Application
X	I-Application
(	O
versions	O
42	O
and	O
later	O
)	O
disabled	O
NPAPI	B-Protocol
support	O
by	O
default	O
.	O
</s>
<s>
However	O
,	O
until	O
September	O
2015	O
(	O
version	O
45	O
)	O
,	O
users	O
could	O
re-enable	O
NPAPI	B-Protocol
.	O
</s>
<s>
Opera	B-Application
dropped	O
support	O
with	O
version	O
37	O
in	O
May	O
2016	O
.	O
</s>
<s>
Mozilla	B-Application
Firefox	I-Application
release	O
52.0	O
in	O
March	O
2017	O
removed	O
all	O
support	O
for	O
NPAPI	B-Protocol
except	O
for	O
Flash	O
.	O
</s>
<s>
Meanwhile	O
,	O
the	O
ESR	O
channel	O
retained	O
general	O
support	O
for	O
this	O
feature	O
with	O
version	O
52	O
ESR	O
being	O
the	O
last	O
NPAPI	B-Protocol
resort	O
.	O
</s>
<s>
Firefox	B-Application
69.0	O
disabled	O
the	O
Flash	O
NPAPI	B-Protocol
by	O
default	O
.	O
</s>
<s>
In	O
Firefox	B-Application
85.0	O
,	O
released	O
in	O
January	O
2021	O
,	O
NPAPI	B-Protocol
support	O
was	O
completely	O
removed	O
.	O
</s>
<s>
In	O
the	O
ESR	O
channel	O
,	O
support	O
for	O
Flash	O
NPAPI	B-Protocol
ended	O
with	O
version	O
78.15.0	O
,	O
released	O
in	O
October	O
2021	O
.	O
</s>
<s>
Safari	B-Application
has	O
dropped	O
support	O
for	O
all	O
NPAPI	B-Protocol
plugins	B-Application
except	O
for	O
Flash	O
with	O
version	O
12	O
released	O
in	O
September	O
2018	O
.	O
</s>
<s>
Flash	O
support	O
has	O
been	O
removed	O
from	O
Safari	B-Application
14	O
,	O
released	O
in	O
September	O
2020	O
.	O
</s>
<s>
SeaMonkey	B-Language
stopped	O
supporting	O
NPAPI	B-Protocol
plugins	B-Application
from	O
version	O
2.53.1	O
,	O
with	O
the	O
exception	O
of	O
Flash	O
.	O
</s>
<s>
NPAPI	B-Protocol
support	O
was	O
completely	O
removed	O
in	O
SeaMonkey	B-Language
2.53.7	O
,	O
released	O
in	O
March	O
2021	O
.	O
</s>
<s>
The	O
following	O
list	O
of	O
web	B-Application
browsers	I-Application
support	O
all	O
NPAPI	B-Protocol
plugins	B-Application
:	O
</s>
<s>
Internet	B-Application
Explorer	I-Application
and	O
browsers	B-Application
based	I-Application
on	I-Application
Internet	I-Application
Explorer	I-Application
use	O
ActiveX	B-Application
controls	I-Application
,	O
ActiveX	B-Application
documents	O
and	O
ActiveX	B-Application
scripting	O
to	O
offer	O
in-page	O
extensibility	O
on	O
par	O
with	O
NPAPI	B-Protocol
.	O
</s>
<s>
Although	O
commonly	O
associated	O
with	O
Internet	B-Application
Explorer	I-Application
,	O
ActiveX	B-Application
is	O
integration	O
technology	O
that	O
allows	O
any	O
computer	O
program	O
to	O
integrate	O
parts	O
of	O
other	O
computer	O
programs	O
that	O
support	O
such	O
integration	O
.	O
</s>
<s>
Internet	B-Application
Explorer	I-Application
,	O
however	O
,	O
is	O
discontinued	O
and	O
its	O
replacement	O
,	O
Microsoft	O
Edge	O
,	O
does	O
not	O
support	O
ActiveX	B-Application
.	O
</s>
<s>
On	O
12	O
August	O
2009	O
a	O
page	O
on	O
Google	B-Protocol
Code	I-Protocol
introduced	O
a	O
new	O
project	O
called	O
Pepper	O
,	O
with	O
the	O
associated	O
Pepper	O
Plugin	B-Application
API	B-Application
(	O
PPAPI	O
)	O
;	O
PPAPI	O
is	O
a	O
derivative	O
of	O
NPAPI	B-Protocol
aimed	O
to	O
make	O
plugins	B-Application
more	O
portable	O
and	O
more	O
secure	O
.	O
</s>
<s>
This	O
extension	O
is	O
designed	O
specifically	O
to	O
ease	O
the	O
implementation	O
of	O
out-of-process	O
plugin	B-Application
execution	O
.	O
</s>
<s>
PPAPI	O
was	O
initially	O
only	O
supported	O
by	O
Google	B-Application
Chrome	I-Application
and	O
Chromium	B-Language
.	O
</s>
<s>
Later	O
,	O
other	O
Chromium-based	O
browsers	B-Application
such	O
as	O
Opera	B-Application
and	O
Vivaldi	B-Language
added	O
PPAPI	O
plugin	B-Application
support	O
.	O
</s>
<s>
In	O
February	O
2012	O
Adobe	O
Systems	O
announced	O
that	O
future	O
Linux	B-Application
versions	O
of	O
Adobe	B-Operating_System
Flash	I-Operating_System
Player	I-Operating_System
would	O
be	O
provided	O
only	O
via	O
PPAPI	O
.	O
</s>
<s>
The	O
previous	O
release	O
,	O
Flash	B-Operating_System
Player	I-Operating_System
11.2	O
,	O
with	O
NPAPI	B-Protocol
support	O
,	O
would	O
receive	O
security	O
updates	O
for	O
five	O
years	O
.	O
</s>
<s>
In	O
August	O
2016	O
Adobe	O
announced	O
that	O
,	O
contrary	O
to	O
their	O
previous	O
statement	O
,	O
it	O
would	O
again	O
support	O
the	O
NPAPI	B-Protocol
Flash	B-Operating_System
Player	I-Operating_System
on	O
Linux	B-Application
and	O
keep	O
releasing	O
new	O
versions	O
of	O
it	O
.	O
</s>
<s>
In	O
August	O
2020	O
,	O
Google	O
announced	O
that	O
support	O
for	O
PPAPI	O
would	O
be	O
removed	O
from	O
Google	B-Application
Chrome	I-Application
and	O
Chromium	B-Language
in	O
June	O
2022	O
.	O
</s>
