<s>
Client-side	B-Operating_System
refers	O
to	O
operations	O
that	O
are	O
performed	O
by	O
the	O
client	B-Protocol
in	O
a	O
client	B-Operating_System
–	I-Operating_System
server	I-Operating_System
relationship	O
in	O
a	O
computer	B-Architecture
network	I-Architecture
.	O
</s>
<s>
Typically	O
,	O
a	O
client	B-Protocol
is	O
a	O
computer	B-Application
application	I-Application
,	O
such	O
as	O
a	O
web	B-Application
browser	I-Application
,	O
that	O
runs	O
on	O
a	O
user	O
's	O
local	O
computer	O
,	O
smartphone	B-Application
,	O
or	O
other	O
device	O
,	O
and	O
connects	O
to	O
a	O
server	B-Application
as	O
necessary	O
.	O
</s>
<s>
Operations	O
may	O
be	O
performed	O
client-side	B-Operating_System
because	O
they	O
require	O
access	O
to	O
information	O
or	O
functionality	O
that	O
is	O
available	O
on	O
the	O
client	B-Protocol
but	O
not	O
on	O
the	O
server	B-Application
,	O
because	O
the	O
user	O
needs	O
to	O
observe	O
the	O
operations	O
or	O
provide	O
input	O
,	O
or	O
because	O
the	O
server	B-Application
lacks	O
the	O
processing	O
power	O
to	O
perform	O
the	O
operations	O
in	O
a	O
timely	O
manner	O
for	O
all	O
of	O
the	O
clients	O
it	O
serves	O
.	O
</s>
<s>
Additionally	O
,	O
if	O
operations	O
can	O
be	O
performed	O
by	O
the	O
client	B-Protocol
,	O
without	O
sending	O
data	O
over	O
the	O
network	O
,	O
they	O
may	O
take	O
less	O
time	O
,	O
use	O
less	O
bandwidth	O
,	O
and	O
incur	O
a	O
lesser	O
security	O
risk	O
.	O
</s>
<s>
When	O
the	O
server	B-Application
serves	O
data	O
in	O
a	O
commonly	O
used	O
manner	O
,	O
for	O
example	O
according	O
to	O
standard	O
protocols	O
such	O
as	O
HTTP	B-Protocol
or	O
FTP	B-Protocol
,	O
users	O
may	O
have	O
their	O
choice	O
of	O
a	O
number	O
of	O
client	B-Protocol
programs	I-Protocol
(	O
e.g.	O
</s>
<s>
most	O
modern	O
web	B-Application
browsers	I-Application
can	O
request	O
and	O
receive	O
data	O
using	O
both	O
HTTP	B-Protocol
and	O
FTP	B-Protocol
)	O
.	O
</s>
<s>
In	O
the	O
case	O
of	O
more	O
specialized	O
applications	O
,	O
programmers	B-Application
may	O
write	O
their	O
own	O
server	B-Application
,	O
client	B-Protocol
,	O
and	O
communications	O
protocol	O
which	O
can	O
only	O
be	O
used	O
with	O
one	O
another	O
.	O
</s>
<s>
Programs	O
that	O
run	O
on	O
a	O
user	O
's	O
local	O
computer	O
without	O
ever	O
sending	O
or	O
receiving	O
data	O
over	O
a	O
network	O
are	O
not	O
considered	O
clients	O
,	O
and	O
so	O
the	O
operations	O
of	O
such	O
programs	O
would	O
not	O
be	O
termed	O
client-side	B-Operating_System
operations	O
.	O
</s>
<s>
In	O
a	O
computer	O
security	O
context	O
,	O
client-side	B-Operating_System
vulnerabilities	O
or	O
attacks	O
refer	O
to	O
those	O
that	O
occur	O
on	O
the	O
client	B-Protocol
/	O
user	O
's	O
computer	O
system	O
,	O
rather	O
than	O
on	O
the	O
server	B-Application
side	I-Application
,	O
or	O
in	O
between	O
the	O
two	O
.	O
</s>
<s>
As	O
an	O
example	O
,	O
if	O
a	O
server	B-Application
contained	O
an	O
encrypted	O
file	O
or	O
message	O
which	O
could	O
only	O
be	O
decrypted	O
using	O
a	O
key	O
housed	O
on	O
the	O
user	O
's	O
computer	O
system	O
,	O
a	O
client-side	B-Operating_System
attack	O
would	O
normally	O
be	O
an	O
attacker	O
's	O
only	O
opportunity	O
to	O
gain	O
access	O
to	O
the	O
decrypted	O
contents	O
.	O
</s>
<s>
For	O
instance	O
,	O
the	O
attacker	O
might	O
cause	O
malware	O
to	O
be	O
installed	O
on	O
the	O
client	B-Protocol
system	O
,	O
allowing	O
the	O
attacker	O
to	O
view	O
the	O
user	O
's	O
screen	O
,	O
record	O
the	O
user	O
's	O
keystrokes	O
,	O
and	O
steal	O
copies	O
of	O
the	O
user	O
's	O
encryption	O
keys	O
,	O
etc	O
.	O
</s>
<s>
Alternatively	O
,	O
an	O
attacker	O
might	O
employ	O
cross-site	O
scripting	O
vulnerabilities	O
to	O
execute	O
malicious	O
code	O
on	O
the	O
client	B-Protocol
's	O
system	O
without	O
needing	O
to	O
install	O
any	O
permanently	O
resident	O
malware	O
.	O
</s>
<s>
Distributed	B-Architecture
computing	I-Architecture
projects	O
such	O
as	O
SETI	B-Application
@home	I-Application
and	O
the	O
Great	O
Internet	O
Mersenne	O
Prime	O
Search	O
,	O
as	O
well	O
as	O
Internet-dependent	O
applications	O
like	O
Google	B-Application
Earth	I-Application
,	O
rely	O
primarily	O
on	O
client-side	B-Operating_System
operations	O
.	O
</s>
<s>
They	O
initiate	O
a	O
connection	O
with	O
the	O
server	B-Application
(	O
either	O
in	O
response	O
to	O
a	O
user	O
query	O
,	O
as	O
with	O
Google	B-Application
Earth	I-Application
,	O
or	O
in	O
an	O
automated	O
fashion	O
,	O
as	O
with	O
SETI	B-Application
@home	I-Application
)	O
,	O
and	O
request	O
some	O
data	O
.	O
</s>
<s>
The	O
server	B-Application
selects	O
a	O
data	O
set	O
(	O
a	O
server-side	B-Application
operation	O
)	O
and	O
sends	O
it	O
back	O
to	O
the	O
client	B-Protocol
.	O
</s>
<s>
The	O
client	B-Protocol
then	O
analyzes	O
the	O
data	O
(	O
a	O
client-side	B-Operating_System
operation	O
)	O
,	O
and	O
,	O
when	O
the	O
analysis	O
is	O
complete	O
,	O
displays	O
it	O
to	O
the	O
user	O
(	O
as	O
with	O
Google	B-Application
Earth	I-Application
)	O
and/or	O
transmits	O
the	O
results	O
of	O
calculations	O
back	O
to	O
the	O
server	B-Application
(	O
as	O
with	O
SETI	B-Application
@home	I-Application
)	O
.	O
</s>
<s>
In	O
the	O
context	O
of	O
the	O
World	O
Wide	O
Web	O
,	O
commonly	O
encountered	O
computer	O
languages	O
which	O
are	O
evaluated	O
or	O
run	O
on	O
the	O
client	B-Protocol
side	I-Protocol
include	O
:	O
</s>
