<s>
Mozilla	B-Application
Firefox	I-Application
has	O
features	O
that	O
allow	O
it	O
to	O
be	O
distinguished	O
from	O
other	O
web	B-Application
browsers	I-Application
,	O
such	O
as	O
Chrome	B-Application
and	O
Internet	B-Application
Explorer	I-Application
.	O
</s>
<s>
To	O
avoid	O
interface	O
bloat	O
,	O
ship	O
a	O
relatively	O
smaller	O
core	O
customizable	O
to	O
meet	O
individual	O
users	O
 '	O
needs	O
,	O
and	O
allow	O
for	O
corporate	O
or	O
institutional	O
extensions	O
to	O
meet	O
their	O
varying	O
policies	O
,	O
Firefox	B-Application
relies	O
on	O
a	O
robust	O
extension	O
system	O
to	O
allow	O
users	O
to	O
modify	O
the	O
browser	B-Application
according	O
to	O
their	O
requirements	O
instead	O
of	O
providing	O
all	O
features	O
in	O
the	O
standard	O
distribution	O
.	O
</s>
<s>
While	O
Opera	B-Application
and	O
Google	B-Application
Chrome	I-Application
do	O
the	O
same	O
,	O
extensions	O
for	O
these	O
are	O
fewer	O
in	O
number	O
as	O
of	O
late	O
2013	O
.	O
</s>
<s>
Internet	B-Application
Explorer	I-Application
also	O
has	O
an	O
extension	O
system	O
but	O
it	O
is	O
less	O
widely	O
supported	O
than	O
that	O
of	O
others	O
.	O
</s>
<s>
Developers	O
supporting	O
multiple	O
browsers	B-Application
almost	O
always	O
support	O
Firefox	B-Application
,	O
and	O
in	O
many	O
instances	O
exclusively	O
.	O
</s>
<s>
As	O
Opera	B-Application
has	O
a	O
policy	O
of	O
deliberately	O
including	O
more	O
features	O
in	O
the	O
core	O
as	O
they	O
prove	O
useful	O
,	O
the	O
market	O
for	O
extensions	O
is	O
relatively	O
unstable	O
but	O
also	O
there	O
is	O
less	O
need	O
for	O
them	O
.	O
</s>
<s>
The	O
sheer	O
number	O
of	O
extensions	O
is	O
not	O
a	O
good	O
guide	O
to	O
the	O
capabilities	O
of	O
a	O
browser	B-Application
.	O
</s>
<s>
Protocol	O
support	O
and	O
the	O
difficulty	O
of	O
adding	O
new	O
link	O
type	O
protocols	O
also	O
vary	O
widely	O
across	O
not	O
only	O
these	O
browsers	B-Application
but	O
across	O
versions	O
of	O
these	O
browsers	B-Application
.	O
</s>
<s>
Opera	B-Application
has	O
historically	O
been	O
most	O
robust	O
and	O
consistent	O
about	O
supporting	O
cutting-edge	O
protocols	O
such	O
as	O
robust	O
file	O
sharing	O
eDonkey	O
links	O
or	O
bitcoin	B-Protocol
transactions	O
.	O
</s>
<s>
These	O
can	O
be	O
difficult	O
to	O
support	O
in	O
Firefox	B-Application
without	O
relying	O
on	O
unknown	O
small	O
developers	O
,	O
which	O
defeats	O
the	O
privacy	O
purpose	O
of	O
these	O
protocols	O
.	O
</s>
<s>
Instructions	O
for	O
supporting	O
new	O
link	O
protocols	O
vary	O
widely	O
across	O
operating	B-General_Concept
systems	I-General_Concept
and	O
Firefox	B-Application
versions	O
,	O
and	O
are	O
generally	O
not	O
implementable	O
by	O
end	O
users	O
who	O
lack	O
systems	O
administration	O
comfort	O
and	O
the	O
ability	O
to	O
follow	O
exact	O
detailed	O
instructions	O
to	O
type	O
in	O
strings	O
.	O
</s>
<s>
Firefox	B-Application
supports	O
most	O
basic	O
Web	O
standards	O
including	O
HTML	B-Language
,	O
XML	B-Protocol
,	O
XHTML	B-Language
,	O
CSS	B-Language
(	O
with	O
extensions	O
)	O
,	O
JavaScript	B-Language
,	O
DOM	B-General_Concept
,	O
MathML	B-Language
,	O
SVG	B-Application
,	O
XSLT	B-Application
and	O
XPath	B-Language
.	O
</s>
<s>
Firefox	B-Application
's	O
standards	O
support	O
and	O
growing	O
popularity	O
have	O
been	O
credited	O
as	O
one	O
reason	O
Internet	B-Application
Explorer	I-Application
7	I-Application
was	O
to	O
be	O
released	O
with	O
improved	O
standards	O
support	O
.	O
</s>
<s>
Since	O
Web	O
standards	O
are	O
often	O
in	O
contradiction	O
with	O
Internet	B-Application
Explorer	I-Application
's	O
behavior	O
,	O
Firefox	B-Application
,	O
like	O
other	O
browsers	B-Application
,	O
has	O
a	O
quirks	B-General_Concept
mode	I-General_Concept
.	O
</s>
<s>
This	O
mode	O
attempts	O
to	O
mimic	O
Internet	B-Application
Explorer	I-Application
's	O
quirks	B-General_Concept
modes	I-General_Concept
,	O
which	O
equates	O
to	O
using	O
obsolete	O
rendering	O
standards	O
dating	O
back	O
to	O
Internet	B-Protocol
Explorer	I-Protocol
5	I-Protocol
,	O
or	O
alternately	O
newer	O
peculiarities	O
introduced	O
in	O
IE	B-Application
6	I-Application
or	O
7	B-Device
.	O
</s>
<s>
Because	O
of	O
the	O
differing	O
rendering	O
,	O
PC	O
World	O
notes	O
that	O
a	O
minority	O
of	O
pages	O
do	O
not	O
work	O
in	O
Firefox	B-Application
,	O
however	O
Internet	B-Application
Explorer	I-Application
7	I-Application
's	O
quirks	B-General_Concept
mode	I-General_Concept
does	O
not	O
either	O
.	O
</s>
<s>
CNET	O
notes	O
that	O
Firefox	B-Application
does	O
not	O
support	O
ActiveX	B-Operating_System
controls	O
by	O
default	O
,	O
which	O
can	O
also	O
cause	O
webpages	O
to	O
be	O
missing	O
features	O
or	O
to	O
not	O
work	O
at	O
all	O
in	O
Firefox	B-Application
.	O
</s>
<s>
Mozilla	O
made	O
the	O
decision	O
to	O
not	O
support	O
ActiveX	B-Operating_System
due	O
to	O
potential	O
security	O
vulnerabilities	O
,	O
its	O
proprietary	O
nature	O
and	O
its	O
lack	O
of	O
cross-platform	O
compatibility	O
.	O
</s>
<s>
There	O
are	O
methods	O
of	O
using	O
ActiveX	B-Operating_System
in	O
Firefox	B-Application
such	O
as	O
via	O
third-party	O
plugins	B-Application
but	O
they	O
do	O
not	O
work	O
in	O
all	O
versions	O
of	O
Firefox	B-Application
or	O
on	O
all	O
platforms	O
.	O
</s>
<s>
Beginning	O
on	O
December	O
8	B-Application
,	O
2006	O
,	O
Firefox	B-Application
Nightly	O
builds	O
pass	O
the	O
Acid2	O
CSS	B-Language
standards	O
compliance	O
test	O
,	O
so	O
all	O
future	O
releases	O
of	O
Firefox	B-Language
3	I-Language
would	O
pass	O
the	O
test	O
.	O
</s>
<s>
Firefox	B-Application
also	O
implements	O
a	O
proprietary	O
protocol	O
from	O
Google	B-Application
called	O
"	O
safebrowsing	O
"	O
,	O
which	O
is	O
not	O
an	O
open	O
standard	O
.	O
</s>
<s>
Mozilla	B-Application
Firefox	I-Application
runs	O
on	O
certain	O
platforms	O
that	O
coincide	O
OS	O
versions	O
in	O
use	O
at	O
the	O
time	O
of	O
release	O
.	O
</s>
<s>
In	O
2004	O
version	O
1	O
supported	O
older	O
operating	B-General_Concept
systems	I-General_Concept
such	O
as	O
Windows	B-Application
95	I-Application
and	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
10.1	I-Operating_System
,	O
by	O
2008	O
version	O
3	O
required	O
at	O
least	O
OS	B-Application
X	I-Application
10.4	I-Application
and	O
even	O
Windows	B-Device
98	I-Device
support	O
ended	O
.	O
</s>
<s>
Various	O
releases	O
available	O
on	O
the	O
primary	O
distribution	O
site	O
can	O
support	O
the	O
following	O
operating	B-General_Concept
systems	I-General_Concept
,	O
although	O
not	O
always	O
the	O
latest	O
Firefox	B-Application
version	O
.	O
</s>
<s>
Various	O
versions	O
of	O
Microsoft	B-Application
Windows	I-Application
,	O
including	O
98	B-Device
,	O
98SE	O
,	O
ME	B-Device
,	O
NT	B-Device
4.0	I-Device
,	O
2000	B-Application
,	O
XP	B-Application
,	O
Server	B-Application
2003	I-Application
,	O
Vista	B-Application
,	O
7	B-Device
,	O
8	B-Application
and	O
10	B-Operating_System
.	O
</s>
<s>
Builds	O
for	O
Solaris	B-Application
(	O
x86	O
and	O
SPARC	O
)	O
,	O
contributed	O
by	O
the	O
Sun	O
Beijing	O
Desktop	O
Team	O
,	O
are	O
available	O
on	O
the	O
Mozilla	O
web	O
site	O
.	O
</s>
<s>
Mozilla	B-Application
Firefox	I-Application
1.x	O
installation	O
on	O
Windows	B-Application
95	I-Application
requires	O
.	O
</s>
<s>
Since	O
Firefox	B-Application
is	O
open	O
source	O
and	O
Mozilla	O
actively	O
develops	O
a	O
platform	B-Application
independent	I-Application
abstraction	I-Application
for	O
its	O
graphical	B-Application
front	I-Application
end	I-Application
,	O
it	O
can	O
also	O
be	O
compiled	O
and	O
run	O
on	O
a	O
variety	O
of	O
other	O
architectures	O
and	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
Thus	O
,	O
Firefox	B-Application
is	O
also	O
available	O
for	O
many	O
other	O
systems	O
.	O
</s>
<s>
This	O
includes	O
OS/2	B-Application
,	O
AIX	B-Application
,	O
and	O
FreeBSD	B-Operating_System
.	O
</s>
<s>
Builds	O
for	O
Windows	B-Operating_System
XP	I-Operating_System
Professional	I-Operating_System
x64	I-Operating_System
Edition	I-Operating_System
are	O
also	O
available	O
.	O
</s>
<s>
Mozilla	B-Application
Firefox	I-Application
is	O
also	O
the	O
browser	B-Application
of	O
choice	O
for	O
a	O
good	O
number	O
of	O
smaller	O
operating	B-General_Concept
systems	I-General_Concept
,	O
such	O
as	O
SkyOS	B-Application
and	O
ZETA	B-Device
.	O
</s>
<s>
Firefox	B-Application
uses	O
the	O
same	O
profile	O
format	O
on	O
the	O
different	O
platforms	O
,	O
so	O
a	O
profile	O
may	O
be	O
used	O
on	O
multiple	O
platforms	O
,	O
if	O
all	O
of	O
the	O
platforms	O
can	O
access	O
the	O
same	O
profile	O
;	O
this	O
includes	O
,	O
for	O
example	O
,	O
profiles	O
stored	O
on	O
an	O
NTFS	B-Application
(	O
via	O
FUSE	B-Application
)	O
or	O
FAT32	B-Application
partition	O
accessible	O
from	O
both	O
Windows	B-Application
and	O
Linux	B-Application
,	O
or	O
on	O
a	O
USB	O
flash	O
drive	O
.	O
</s>
<s>
Firefox	B-Application
is	O
free-libre	O
software	O
,	O
and	O
thus	O
in	O
particular	O
its	O
source	O
code	O
is	O
visible	O
to	O
everyone	O
.	O
</s>
<s>
It	O
also	O
allowed	O
the	O
U.S.	O
Department	O
of	O
Homeland	O
Security	O
to	O
give	O
funding	O
for	O
the	O
automated	O
tool	O
Coverity	O
to	O
be	O
run	O
against	O
Firefox	B-Application
code	O
.	O
</s>
<s>
Firefox	B-Application
supports	O
tabbed	O
browsing	O
,	O
which	O
allows	O
users	O
to	O
open	O
several	O
pages	O
in	O
one	O
window	O
.	O
</s>
<s>
This	O
feature	O
was	O
carried	O
over	O
from	O
the	O
Mozilla	B-Language
Application	I-Language
Suite	I-Language
,	O
which	O
in	O
turn	O
had	O
borrowed	O
the	O
feature	O
from	O
the	O
popular	O
extension	O
for	O
Mozilla	O
.	O
</s>
<s>
Firefox	B-Application
also	O
permits	O
the	O
"	O
homepage	O
"	O
to	O
be	O
a	O
list	O
of	O
URLs	O
delimited	O
with	O
vertical	O
bars	O
( |	O
)	O
,	O
which	O
are	O
automatically	O
opened	O
in	O
separate	O
tabs	O
,	O
rather	O
than	O
a	O
single	O
page	O
.	O
</s>
<s>
Firefox	B-Application
2	O
supports	O
more	O
tabbed	O
browsing	O
features	O
,	O
including	O
a	O
"	O
tab	O
overflow	O
"	O
solution	O
that	O
keeps	O
the	O
user	O
's	O
tabs	O
easily	O
accessible	O
when	O
they	O
would	O
otherwise	O
become	O
illegible	O
,	O
a	O
"	O
session	O
store	O
"	O
which	O
lets	O
the	O
user	O
keep	O
the	O
opened	O
tabs	O
across	O
the	O
restarts	O
,	O
and	O
an	O
"	O
undo	O
close	O
tab	O
"	O
feature	O
.	O
</s>
<s>
Firefox	B-Application
also	O
includes	O
integrated	O
customizable	O
pop-up	O
blocking	O
.	O
</s>
<s>
Firefox	B-Application
was	O
given	O
this	O
feature	O
early	O
in	O
beta	O
development	O
,	O
and	O
it	O
was	O
a	O
major	O
comparative	O
selling	O
point	O
of	O
the	O
browser	B-Application
until	O
Internet	B-Application
Explorer	I-Application
gained	O
the	O
capability	O
in	O
the	O
Windows	B-Application
XP	I-Application
SP2	O
release	O
of	O
August	O
25	O
,	O
2004	O
.	O
</s>
<s>
Firefox	B-Application
's	O
pop-up	O
blocking	O
can	O
be	O
turned	O
off	O
entirely	O
to	O
allow	O
pop-ups	O
from	O
all	O
sites	O
.	O
</s>
<s>
Firefox	B-Application
's	O
pop-up	O
blocking	O
can	O
be	O
inconvenient	O
at	O
times	O
it	O
prevents	O
JavaScript-based	O
links	O
from	O
opening	O
a	O
new	O
window	O
while	O
a	O
page	O
is	O
loading	O
unless	O
the	O
site	O
is	O
added	O
to	O
a	O
"	O
safe	O
list	O
"	O
found	O
in	O
the	O
options	O
menu	O
.	O
</s>
<s>
By	O
default	O
,	O
Firefox	B-Application
downloads	O
all	O
files	O
to	O
a	O
user	O
's	O
desktop	O
on	O
Mac	O
and	O
Windows	B-Application
or	O
to	O
the	O
user	O
's	O
home	O
directory	O
on	O
Linux	B-Application
,	O
but	O
it	O
can	O
be	O
configured	O
to	O
prompt	O
for	O
a	O
specific	O
download	O
location	O
.	O
</s>
<s>
Version	O
3.0	O
added	O
support	O
for	O
cross-session	O
resuming	O
(	O
stopping	O
a	O
download	O
and	O
resuming	O
it	O
after	O
closing	O
the	O
browser	B-Application
)	O
.	O
</s>
<s>
From	O
2004	O
,	O
live	O
bookmarks	O
allowed	O
users	O
to	O
dynamically	O
monitor	O
changes	O
to	O
their	O
favorite	O
news	O
sources	O
,	O
using	O
RSS	O
or	O
Atom	B-Application
feeds	I-Application
.	O
</s>
<s>
Instead	O
of	O
treating	O
RSS-feeds	O
as	O
HTML	B-Language
pages	O
as	O
most	O
news	B-Application
aggregators	I-Application
do	O
,	O
Firefox	B-Application
treated	O
them	O
as	O
bookmarks	O
and	O
automatically	O
updated	O
them	O
in	O
real-time	O
with	O
a	O
link	O
to	O
the	O
appropriate	O
source	O
.	O
</s>
<s>
In	O
December	O
2018	O
,	O
version	O
64.0	O
of	O
Firefox	B-Application
removed	O
live	O
bookmarks	O
and	O
web	B-General_Concept
feeds	I-General_Concept
,	O
with	O
Mozilla	O
suggesting	O
its	O
replacement	O
by	O
add-ons	B-Operating_System
or	O
other	O
software	O
with	O
news	B-Application
aggregator	I-Application
functionality	O
like	O
Mozilla	B-Application
Thunderbird	I-Application
.	O
</s>
<s>
Firefox	B-Application
also	O
has	O
an	O
incremental	B-Application
find	I-Application
feature	O
known	O
as	O
"	O
Find	B-Application
as	I-Application
you	I-Application
type	I-Application
"	O
,	O
invoked	O
by	O
pressing	O
Ctrl+F	O
.	O
</s>
<s>
With	O
this	O
feature	O
enabled	O
,	O
a	O
user	O
can	O
simply	O
begin	O
typing	O
a	O
word	O
while	O
viewing	O
a	O
web	O
page	O
,	O
and	O
Firefox	B-Application
automatically	O
searches	O
for	O
it	O
and	O
highlights	O
the	O
first	O
instance	O
found	O
.	O
</s>
<s>
As	O
the	O
user	O
types	O
more	O
of	O
the	O
word	O
,	O
Firefox	B-Application
refines	O
its	O
search	O
.	O
</s>
<s>
In	O
this	O
mode	O
highlighted	O
links	O
can	O
be	O
followed	O
by	O
pressing	O
the	O
enter	B-Device
key	I-Device
.	O
</s>
<s>
A	O
built-in	O
Mycroft	O
Web	O
search	O
function	O
features	O
extensible	O
search-engine	O
listing	O
;	O
by	O
default	O
,	O
Firefox	B-Application
includes	O
plugins	B-Application
for	O
Google	B-Application
and	O
Yahoo	O
!,	O
and	O
also	O
includes	O
plugins	B-Application
for	O
looking	O
up	O
a	O
word	O
on	O
dictionary.com	O
and	O
browsing	O
through	O
Amazon.com	B-Application
listings	O
.	O
</s>
<s>
Other	O
popular	O
Mycroft	O
search	O
engines	O
include	O
Wikipedia	O
,	O
eBay	B-Application
,	O
and	O
IMDb	O
.	O
</s>
<s>
Smart	B-Protocol
Bookmarks	I-Protocol
(	O
aka	O
Smart	B-Operating_System
keywords	I-Operating_System
)	O
can	O
be	O
used	O
to	O
quickly	O
search	O
for	O
information	O
on	O
specific	O
Web	O
sites	O
.	O
</s>
<s>
A	O
smart	B-Operating_System
keyword	I-Operating_System
is	O
defined	O
by	O
the	O
user	O
and	O
can	O
be	O
associated	O
with	O
any	O
bookmark	O
,	O
and	O
can	O
then	O
be	O
used	O
in	O
the	O
address	O
bar	O
as	O
a	O
shortcut	O
to	O
quickly	O
get	O
to	O
the	O
site	O
or	O
,	O
if	O
the	O
smart	B-Operating_System
keyword	I-Operating_System
is	O
linked	O
to	O
a	O
searchbox	O
,	O
to	O
search	O
the	O
site	O
.	O
</s>
<s>
For	O
example	O
,	O
"	O
imdb	O
"	O
is	O
a	O
pre-defined	O
smart	B-Operating_System
keyword	I-Operating_System
;	O
to	O
search	O
for	O
information	O
about	O
the	O
movie	O
'	O
Firefox	B-Application
 '	O
on	O
IMDb	O
,	O
jump	O
to	O
the	O
location	O
bar	O
with	O
the	O
+	O
shortcut	O
,	O
type	O
"	O
imdb	O
Firefox	B-Application
"	O
and	O
press	O
the	O
Enter	B-Device
key	I-Device
or	O
just	O
simply	O
type	O
in	O
"	O
imdb	O
"	O
if	O
one	O
wants	O
to	O
get	O
to	O
the	O
frontpage	O
instead	O
.	O
</s>
<s>
The	O
Chrome	B-Application
packages	O
within	O
Firefox	B-Application
control	O
and	O
implement	O
the	O
Firefox	B-Application
user	O
interface	O
.	O
</s>
<s>
Search	O
term	O
suggestions	O
will	O
now	O
appear	O
as	O
users	O
type	O
in	O
the	O
integrated	O
search	O
box	O
when	O
using	O
the	B-Application
Google	I-Application
,	O
Yahoo	B-Application
!	I-Application
</s>
<s>
A	O
new	O
search	O
engine	O
manager	O
makes	O
it	O
easier	O
to	O
add	O
,	O
remove	O
and	O
re-order	O
search	O
engines	O
,	O
and	O
users	O
will	O
be	O
alerted	O
when	O
Firefox	B-Application
encounters	O
a	O
website	O
that	O
offers	O
new	O
search	O
engines	O
that	O
the	O
user	O
may	O
wish	O
to	O
install	O
.	O
</s>
<s>
Microsummaries	O
can	O
either	O
be	O
provided	O
by	O
the	O
page	O
,	O
or	O
be	O
generated	O
by	O
the	O
processing	O
of	O
an	O
XSLT	B-Application
stylesheet	O
against	O
the	O
page	O
.	O
</s>
<s>
In	O
the	O
latter	O
case	O
,	O
the	O
XSLT	B-Application
stylesheet	O
and	O
the	O
page	O
that	O
the	O
microsummary	O
applies	O
to	O
are	O
provided	O
by	O
a	O
microsummary	O
generator	O
.	O
</s>
<s>
Support	O
for	O
Microsummaries	O
was	O
removed	O
as	O
of	O
Firefox	B-Application
6	B-Application
.	O
</s>
<s>
Support	O
for	O
Live	O
Titles	O
was	O
removed	O
as	O
of	O
Firefox	B-Application
6	B-Application
.	O
</s>
<s>
The	O
Session	O
Restore	O
feature	O
restores	O
windows	B-Application
,	O
tabs	O
,	O
text	O
typed	O
in	O
forms	O
,	O
and	O
in-progress	O
downloads	O
from	O
the	O
last	O
user	O
session	O
.	O
</s>
<s>
Firefox	B-Application
2	O
was	O
designed	O
for	O
the	O
average	O
user	O
,	O
hiding	O
advanced	O
configuration	O
and	O
making	O
features	O
that	O
do	O
not	O
require	O
user	O
interaction	O
to	O
function	O
.	O
</s>
<s>
Jim	O
Repoza	O
of	O
eWEEK	O
states	O
:	O
Firefox	B-Application
also	O
won	O
UK	O
Usability	O
Professionals	O
 '	O
Association	O
's	O
2005	O
award	O
for	O
"	O
Best	O
software	O
application	O
"	O
.	O
</s>
<s>
Firefox	B-Application
10	B-Operating_System
added	O
the	O
CSS	B-Language
Style	I-Language
Inspector	O
to	O
the	O
Page	O
Inspector	O
,	O
which	O
allow	O
users	O
to	O
check	O
out	O
a	O
site	O
's	O
structure	O
and	O
edit	O
the	O
CSS	B-Language
without	O
leaving	O
the	O
browser	B-Application
.	O
</s>
<s>
Firefox	B-Application
10	B-Operating_System
added	O
support	O
for	O
CSS	B-Language
3D	O
Transforms	O
and	O
for	O
anti-aliasing	B-Algorithm
in	O
the	O
WebGL	O
standard	O
for	O
hardware-accelerated	B-General_Concept
3D	O
graphics	O
.	O
</s>
<s>
These	O
updates	O
mean	O
that	O
complex	O
site	O
and	O
Web	O
app	O
animations	O
will	O
render	O
more	O
smoothly	O
in	O
Firefox	B-Application
,	O
and	O
that	O
developers	O
can	O
animate	O
2D	O
objects	O
into	O
3D	O
without	O
plug-ins	B-Application
.	O
</s>
<s>
Firefox	B-Application
11	O
,	O
released	O
January	O
2012	O
,	O
introduced	O
a	O
tiltable	O
three-dimensional	O
visualization	O
of	O
the	O
Document	B-General_Concept
Object	I-General_Concept
Model	I-General_Concept
(	O
DOM	B-General_Concept
)	O
,	O
where	O
more	O
nested	O
elements	O
protrude	O
further	O
from	O
the	O
page	O
surface	O
.	O
</s>
<s>
On	O
August	O
21	O
,	O
2015	O
,	O
Firefox	B-Application
developers	O
announced	O
that	O
due	O
to	O
planned	O
changes	O
to	O
Firefox	B-Application
's	O
internal	O
operations	O
,	O
including	O
the	O
planned	O
implementation	O
of	O
a	O
new	O
multi-process	O
architecture	O
codenamed	O
"	O
Multiprocess	O
Firefox	B-Application
"	O
or	O
"	O
Electrolysis	O
"	O
(	O
stylized	O
"	O
e10s	O
"	O
)	O
,	O
introduced	O
to	O
some	O
users	O
in	O
version	O
48	O
,	O
Firefox	B-Application
adopted	O
a	O
new	O
extension	O
architecture	O
known	O
as	O
WebExtensions	B-Operating_System
,	O
available	O
to	O
desktop	O
version	O
and	O
Firefox	B-Application
for	I-Application
Android	I-Application
(	O
considered	O
stable	O
in	O
version	O
48	O
)	O
.	O
</s>
<s>
WebExtensions	B-Operating_System
uses	O
HTML	B-Language
and	O
JavaScript	B-Language
APIs	B-Application
and	O
is	O
designed	O
to	O
be	O
similar	O
to	O
the	B-Application
Google	I-Application
Chrome	B-Application
and	O
Microsoft	B-Application
Edge	I-Application
extension	O
systems	O
,	O
and	O
run	O
within	O
a	O
multi-process	O
environment	O
,	O
but	O
does	O
not	O
enable	O
the	O
same	O
level	O
of	O
access	O
to	O
the	O
browser	B-Application
.	O
</s>
<s>
Support	O
for	O
XPCOM	O
and	O
XUL	O
add-ons	B-Operating_System
are	O
no	O
longer	O
offered	O
beginning	O
with	O
Firefox	B-Application
57	O
.	O
</s>
<s>
Firefox	B-Application
83	O
introduced	O
HTTPS-only	O
mode	O
,	O
a	O
security	O
enhancing	O
mode	O
that	O
once	O
enabled	O
forces	O
all	O
connections	O
to	O
websites	O
to	O
use	O
HTTPS	O
.	O
</s>
<s>
Firefox	B-Language
3	I-Language
includes	O
a	O
"	O
Smart	O
Location	O
Bar	O
"	O
.	O
</s>
<s>
While	O
most	O
other	O
browsers	B-Application
,	O
such	O
as	O
Internet	B-Application
Explorer	I-Application
,	O
will	O
search	O
through	O
history	O
for	O
matching	O
web	O
sites	O
as	O
the	O
user	O
types	O
a	O
URL	O
into	O
the	O
location	O
bar	O
,	O
the	O
Smart	O
Location	O
Bar	O
will	O
also	O
search	O
through	O
bookmarks	O
for	O
a	O
page	O
with	O
a	O
matching	O
URL	O
.	O
</s>
<s>
Additionally	O
,	O
Firefox	B-Application
's	O
Smart	O
Location	O
Bar	O
will	O
also	O
search	O
through	O
page	O
titles	O
,	O
allowing	O
the	O
user	O
to	O
type	O
in	O
a	O
relevant	O
keyword	O
,	O
instead	O
of	O
a	O
URL	O
,	O
to	O
find	O
the	O
desired	O
page	O
.	O
</s>
<s>
Firefox	B-Application
uses	O
frecency	O
and	O
other	O
heuristics	O
to	O
predict	O
which	O
history	O
and	O
bookmark	O
matches	O
the	O
user	O
is	O
most	O
likely	O
to	O
select	O
.	O
</s>
<s>
Smart	B-Protocol
Bookmark	I-Protocol
Folders	O
can	O
be	O
created	O
by	O
saving	O
a	O
search	O
query	O
in	O
the	O
Library	O
.	O
</s>
<s>
Similar	O
support	O
is	O
available	O
for	O
other	O
protocols	O
(	O
Web	O
applications	O
will	O
have	O
to	O
first	O
enable	O
this	O
by	O
registering	O
as	O
handlers	O
with	O
Firefox	B-Application
)	O
.	O
</s>
<s>
There	O
are	O
six	O
types	O
of	O
add-ons	B-Operating_System
in	O
Firefox	B-Application
:	O
extensions	O
,	O
themes	B-Application
,	O
language	B-General_Concept
packs	I-General_Concept
,	O
plugins	B-Application
,	O
social	O
features	O
and	O
apps	O
.	O
</s>
<s>
Firefox	B-Operating_System
add-ons	I-Operating_System
may	O
be	O
obtained	O
from	O
the	O
Mozilla	O
Add-ons	B-Operating_System
web	O
site	O
or	O
from	O
other	O
sources	O
.	O
</s>
<s>
Firefox	B-Application
users	O
can	O
add	O
features	O
and	O
change	O
functionality	O
in	O
Firefox	B-Application
by	O
installing	O
extensions	O
.	O
</s>
<s>
Features	O
that	O
the	O
Firefox	B-Application
developers	O
believe	O
will	O
be	O
used	O
by	O
only	O
a	O
small	O
number	O
of	O
its	O
users	O
are	O
not	O
included	O
in	O
Firefox	B-Application
,	O
but	O
instead	O
left	O
to	O
be	O
implemented	O
as	O
extensions	O
.	O
</s>
<s>
Many	O
Mozilla	B-Language
Suite	I-Language
features	O
,	O
such	O
as	O
IRC	O
chat	O
(	O
ChatZilla	B-Operating_System
)	O
and	O
calendar	B-Application
have	O
been	O
recreated	O
as	O
Firefox	B-Application
extensions	O
.	O
</s>
<s>
Like	O
applications	O
on	O
Android	B-Application
and	O
iOS	B-Application
,	O
Firefox	B-Application
extensions	O
have	O
permission	O
model	O
:	O
for	O
example	O
before	O
installing	O
of	O
extension	O
user	O
must	O
agree	O
that	O
this	O
extension	O
can	O
have	O
access	O
to	O
all	O
webpages	O
,	O
or	O
maybe	O
have	O
permission	O
to	O
manage	O
downloads	O
,	O
or	O
have	O
no	O
special	O
permissions	O
—	O
in	O
such	O
way	O
the	O
extension	O
can	O
be	O
manually	O
activated	O
and	O
interact	O
with	O
current	O
page	O
.	O
</s>
<s>
From	O
2019	O
Firefox	B-Application
,	O
Chromium	B-Language
based	O
browsers	B-Application
(	O
Google	B-Application
Chrome	I-Application
,	O
Edge	B-Application
,	O
Opera	B-Application
,	O
Vivaldi	B-Language
)	O
have	O
the	O
same	O
format	O
of	O
extension	O
:	O
WebExtensions	B-Operating_System
API	B-Application
,	O
this	O
is	O
mean	O
that	O
web	O
extension	O
developed	O
for	O
Google	B-Application
Chrome	I-Application
can	O
be	O
used	O
on	O
Firefox	B-Application
(	O
in	O
most	O
cases	O
)	O
,	O
and	O
vice	O
versa	O
.	O
</s>
<s>
Firefox	B-Application
also	O
supports	O
a	O
variety	O
of	O
themes	B-Application
for	O
changing	O
its	O
appearance	O
.	O
</s>
<s>
Prior	O
to	O
the	O
release	O
of	O
Firefox	B-Application
57	O
,	O
themes	B-Application
are	O
simply	O
packages	O
of	O
CSS	B-Language
and	O
image	O
files	O
.	O
</s>
<s>
From	O
Firefox	B-Application
57	O
onwards	O
,	O
themes	B-Application
consist	O
solely	O
of	O
color	O
modifications	O
through	O
the	O
use	O
of	O
CSS	B-Language
.	O
</s>
<s>
Many	O
themes	B-Application
can	O
be	O
downloaded	O
from	O
the	O
Mozilla	B-Operating_System
Update	I-Operating_System
web	O
site	O
.	O
</s>
<s>
Language	B-General_Concept
packs	I-General_Concept
are	O
dictionaries	O
for	O
spell	O
checking	O
of	O
input	O
fields	O
.	O
</s>
<s>
Firefox	B-Application
supports	O
plugins	B-Application
based	O
on	O
Netscape	O
Plugin	B-Application
Application	B-Application
Program	I-Application
Interface	I-Application
(	O
NPAPI	B-Protocol
)	O
,	O
i.e.	O
</s>
<s>
Netscape-style	O
plugins	B-Application
.	O
</s>
<s>
As	O
a	O
side	O
note	O
,	O
Opera	B-Application
and	O
Internet	B-Application
Explorer	I-Application
3.0	O
to	O
5.0	O
also	O
support	O
NPAPI	B-Protocol
.	O
</s>
<s>
On	O
June	O
30	O
,	O
2004	O
,	O
the	O
Mozilla	O
Foundation	O
,	O
in	O
partnership	O
with	O
Adobe	O
,	O
Apple	O
,	O
Macromedia	O
,	O
Opera	B-Application
,	O
and	O
Sun	O
Microsystems	O
,	O
a	O
series	O
of	O
changes	O
to	O
web	B-Application
browser	I-Application
plugins	B-Application
.	O
</s>
<s>
The	O
then-new	O
API	B-Application
allowed	O
web	O
developers	O
to	O
offer	O
,	O
helping	O
to	O
maintain	O
innovation	O
and	O
standards	O
.	O
</s>
<s>
The	O
then-new	O
plugin	B-Application
technologies	O
were	O
implemented	O
in	O
the	O
future	O
versions	O
of	O
the	O
Mozilla	O
applications	O
.	O
</s>
<s>
Mozilla	B-Application
Firefox	I-Application
1.5	O
and	O
later	O
versions	O
include	O
the	O
Java	O
Embedding	O
plugin	B-Application
,	O
which	O
allow	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
users	O
to	O
run	O
Java	O
applets	O
with	O
the	O
then-latest	O
1.4	O
and	O
5.0	O
versions	O
of	O
Java	O
(	O
the	O
default	O
Java	O
software	O
shipped	O
by	O
Apple	O
is	O
not	O
compatible	O
with	O
any	O
browser	B-Application
,	O
except	O
its	O
own	O
Safari	O
)	O
.	O
</s>
<s>
After	O
the	O
releases	O
of	O
Firefox	B-Operating_System
OS	I-Operating_System
based	O
on	O
stack	O
of	O
web	O
technologies	O
,	O
Mozilla	O
added	O
a	O
feature	O
to	O
install	O
mobile	O
apps	O
on	O
PC	O
using	O
Firefox	B-Application
as	O
base	O
.	O
</s>
<s>
Beyond	O
the	O
use	O
of	O
Add-ons	B-Operating_System
,	O
Firefox	B-Application
additional	O
customization	O
features	O
.	O
</s>
<s>
User	O
stylesheets	O
to	O
change	O
the	O
style	O
of	O
webpages	O
and	O
Firefox	B-Application
's	O
user	O
interface	O
.	O
</s>
<s>
A	O
number	O
of	O
internal	O
configuration	O
options	O
are	O
not	O
accessible	O
in	O
a	O
conventional	O
manner	O
through	O
Firefox	B-Application
's	O
preference	O
dialogs	O
,	O
although	O
they	O
are	O
exposed	O
through	O
its	O
about:config	O
interface	O
.	O
</s>
