<s>
MicroB	B-Protocol
was	O
a	O
mobile	B-Application
web	I-Application
browser	I-Application
developed	O
by	O
Nokia	O
for	O
use	O
in	O
smartphones	B-Application
and	O
mobile	B-Application
devices	I-Application
that	O
run	O
the	O
Maemo	B-Operating_System
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
The	O
browser	O
is	O
Mozilla-based	O
and	O
uses	O
the	O
Gecko	B-Language
layout	I-Language
engine	I-Language
.	O
</s>
<s>
It	O
is	O
shipped	O
with	O
Nokia	O
's	O
N800	B-Application
,	O
N810	B-Language
and	O
N900	B-Application
Internet	O
Tablets	O
,	O
and	O
is	O
also	O
available	O
for	O
the	O
770	B-Application
via	O
the	O
'	O
Hacker	O
Editions	O
 '	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
In	O
place	O
of	O
Mozilla	B-Operating_System
's	O
XUL-based	O
user	B-Application
interface	I-Application
,	O
MicroB	B-Protocol
uses	O
the	O
Maemo-native	O
(	O
GTK-based	O
)	O
Hildon	B-Language
API	I-Language
and	O
widgets	O
.	O
</s>
<s>
MicroB	B-Protocol
was	O
initially	O
released	O
as	O
a	O
public	O
beta	O
for	O
Internet	B-Operating_System
Tablet	I-Operating_System
OS	I-Operating_System
2007	O
on	O
July	O
17	O
,	O
2007	O
to	O
allow	O
third-party	O
developers	O
and	O
community	O
members	O
to	O
develop	O
and	O
port	O
plugins	B-Application
,	O
and	O
help	O
shape	O
the	O
development	O
of	O
the	O
browser	O
.	O
</s>
<s>
It	O
was	O
updated	O
several	O
times	O
before	O
it	O
replaced	O
Opera	B-Application
as	O
Internet	B-Operating_System
Tablet	I-Operating_System
OS	I-Operating_System
's	O
default	O
browser	O
with	O
the	O
release	O
of	O
Internet	B-Operating_System
Tablet	I-Operating_System
OS	I-Operating_System
2008	O
on	O
November	O
18	O
,	O
2007	O
with	O
the	O
N810	B-Language
.	O
</s>
<s>
MicroB	B-Protocol
is	O
Mozilla-based	O
and	O
uses	O
the	O
Gecko	B-Language
engine	I-Language
,	O
but	O
a	O
number	O
of	O
features	O
are	O
omitted	O
due	O
to	O
platform-specific	O
limitations	O
.	O
</s>
<s>
In	O
particular	O
,	O
SVG	B-Application
support	O
is	O
disabled	O
due	O
to	O
unacceptable	O
performance	O
,	O
and	O
XUL	B-Application
is	O
not	O
included	O
to	O
reduce	O
size	O
and	O
decrease	O
memory	O
consumption	O
.	O
</s>
<s>
As	O
XUL	B-Application
is	O
not	O
included	O
,	O
most	O
Firefox	O
plugins	B-Application
require	O
porting	O
and	O
repackaging	O
before	O
they	O
can	O
be	O
used	O
with	O
MicroB	B-Protocol
.	O
</s>
<s>
In	O
place	O
of	O
XUL	B-Application
,	O
MicroB	B-Protocol
uses	O
GTK	B-Application
and	O
the	O
Hildon	B-Language
UI	I-Language
toolkit	O
to	O
provide	O
a	O
native	O
interface	O
.	O
</s>
<s>
The	O
Maemo	B-Operating_System
Browser	O
Extras	O
project	O
is	O
responsible	O
for	O
a	O
large	O
number	O
of	O
the	O
available	O
add-ons	O
.	O
</s>
<s>
Greasemonkey	B-Operating_System
–	O
All	O
scripts	O
that	O
work	O
on	O
the	O
desktop	O
version	O
of	O
Firefox	O
work	O
fine	O
in	O
MicroB	B-Protocol
,	O
extending	O
the	O
capabilities	O
of	O
the	O
browser	O
and	O
even	O
replacing	O
the	O
need	O
for	O
some	O
extensions	O
which	O
are	O
not	O
available	O
for	O
MicroB	B-Protocol
.	O
</s>
