<s>
Flashblock	B-Operating_System
is	O
a	O
discontinued	O
Flash	O
content-filtering	O
Firefox	B-Operating_System
extension	I-Operating_System
for	O
Mozilla	B-Application
Firefox	I-Application
and	O
SeaMonkey	B-Language
.	O
</s>
<s>
Flashblock	B-Operating_System
allows	O
users	O
to	O
prevent	O
page	O
elements	O
,	O
such	O
as	O
HTML	O
object	O
tag	O
browser	B-Application
plug-ins	I-Application
and	O
advertisements	O
,	O
from	O
being	O
displayed	O
.	O
</s>
<s>
Flashblock	B-Operating_System
neither	O
stops	O
the	O
download	O
of	O
Flash	O
content	O
nor	O
does	O
it	O
prevent	O
its	O
execution	O
completely	O
.	O
</s>
<s>
The	O
extension	O
uses	O
XBL	B-Application
and	O
CSS	B-Language
to	O
prevent	O
elements	O
of	O
Silverlight	B-Application
,	O
Macromedia	B-Application
Authorware	I-Application
,	O
Adobe	B-Operating_System
Director	I-Operating_System
and	O
Adobe	B-Operating_System
Flash	I-Operating_System
from	O
being	O
displayed	O
.	O
</s>
<s>
Flashblock	B-Operating_System
does	O
not	O
prevent	O
the	O
elements	O
from	O
being	O
downloaded	O
.	O
</s>
<s>
Flashblock	B-Operating_System
provides	O
a	O
mechanism	O
that	O
allows	O
users	O
to	O
display	O
the	O
blocked	O
elements	O
by	O
clicking	O
on	O
them	O
,	O
or	O
by	O
whitelisting	O
.	O
</s>
<s>
Flashblock	B-Operating_System
is	O
based	O
on	O
a	O
bookmarklet	B-Language
by	O
Jesse	O
Ruderman	O
.	O
</s>
<s>
In	O
2006	O
,	O
InformationWeek	O
recommended	O
Flashblock	B-Operating_System
,	O
and	O
described	O
it	O
as	O
one	O
of	O
the	O
most	O
popular	O
Firefox	B-Operating_System
extensions	I-Operating_System
.	O
</s>
<s>
It	O
was	O
reviewed	O
by	O
download.com	B-Application
in	O
2011	O
,	O
by	O
Softpedia	O
,	O
and	O
in	O
2016	O
Tomsguide.com	O
included	O
it	O
in	O
its	O
"	O
40	O
Best	O
Firefox	B-Application
Browser	I-Application
Add-Ons	B-Operating_System
"	O
.	O
</s>
