<s>
In	O
computing	O
,	O
POST	O
is	O
a	O
request	O
method	O
supported	O
by	O
HTTP	B-Protocol
used	O
by	O
the	O
World	O
Wide	O
Web	O
.	O
</s>
<s>
By	O
design	O
,	O
the	O
POST	B-Protocol
request	I-Protocol
method	O
requests	O
that	O
a	O
web	O
server	O
accept	O
the	O
data	O
enclosed	O
in	O
the	O
body	O
of	O
the	O
request	O
message	O
,	O
most	O
likely	O
for	O
storing	O
it	O
.	O
</s>
<s>
It	O
is	O
often	O
used	O
when	O
uploading	O
a	O
file	O
or	O
when	O
submitting	O
a	O
completed	O
web	B-General_Concept
form	I-General_Concept
.	O
</s>
<s>
In	O
contrast	O
,	O
the	O
HTTP	B-Protocol
GET	O
request	O
method	O
retrieves	O
information	O
from	O
the	O
server	O
.	O
</s>
<s>
As	O
part	O
of	O
a	O
GET	O
request	O
,	O
some	O
data	O
can	O
be	O
passed	O
within	O
the	O
URL	O
's	O
query	B-Protocol
string	I-Protocol
,	O
specifying	O
(	O
for	O
example	O
)	O
search	O
terms	O
,	O
date	O
ranges	O
,	O
or	O
other	O
information	O
that	O
defines	O
the	O
query	O
.	O
</s>
<s>
As	O
part	O
of	O
a	O
POST	B-Protocol
request	I-Protocol
,	O
an	O
arbitrary	O
amount	O
of	O
data	O
of	O
any	O
type	O
can	O
be	O
sent	O
to	O
the	O
server	O
in	O
the	O
body	O
of	O
the	O
request	O
message	O
.	O
</s>
<s>
A	O
header	B-Protocol
field	I-Protocol
in	O
the	O
POST	B-Protocol
request	I-Protocol
usually	O
indicates	O
the	O
message	O
body	O
's	O
Internet	B-Application
media	I-Application
type	I-Application
.	O
</s>
<s>
The	O
world	O
wide	O
Web	O
and	O
HTTP	B-Protocol
are	O
based	O
on	O
a	O
number	O
of	O
request	O
methods	O
or	O
'	O
verbs	O
 '	O
,	O
including	O
POST	O
and	O
GET	O
as	O
well	O
as	O
PUT	O
,	O
DELETE	O
,	O
and	O
several	O
others	O
.	O
</s>
<s>
Web	O
browsers	O
normally	O
use	O
only	O
GET	O
and	O
POST	O
,	O
but	O
RESTful	B-Protocol
online	O
apps	B-Application
make	O
use	O
of	O
many	O
of	O
the	O
others	O
.	O
</s>
<s>
POST	O
's	O
place	O
in	O
the	O
range	O
of	O
HTTP	B-Protocol
methods	O
is	O
to	O
send	O
a	O
representation	O
of	O
a	O
new	O
data	B-Architecture
entity	I-Architecture
to	O
the	O
server	O
so	O
that	O
it	O
will	O
be	O
stored	O
as	O
a	O
new	O
subordinate	O
of	O
the	O
resource	O
identified	O
by	O
the	O
URI	B-Protocol
.	O
</s>
<s>
For	O
example	O
,	O
for	O
the	O
URI	B-Protocol
http://example.com/customers	O
,	O
POST	B-Protocol
requests	I-Protocol
might	O
be	O
expected	O
to	O
represent	O
new	O
customers	O
,	O
each	O
including	O
their	O
name	O
,	O
address	O
,	O
contact	O
details	O
and	O
so	O
on	O
.	O
</s>
<s>
First	O
,	O
there	O
is	O
no	O
technical	O
reason	O
for	O
a	O
URI	B-Protocol
to	O
textually	O
describe	O
the	O
web	O
resource	O
subordinate	O
to	O
which	O
POST	O
data	O
will	O
be	O
stored	O
.	O
</s>
<s>
In	O
fact	O
,	O
unless	O
some	O
effort	O
is	O
made	O
,	O
the	O
last	O
part	O
of	O
a	O
URI	B-Protocol
will	O
more	O
likely	O
describe	O
the	O
web	O
application	O
's	O
processing	O
page	O
and	O
its	O
technology	O
,	O
such	O
as	O
http://example.com/applicationform.php	O
.	O
</s>
<s>
Web	B-Application
application	I-Application
frameworks	I-Application
such	O
as	O
Ruby	B-Application
on	I-Application
Rails	I-Application
and	O
others	O
make	O
it	O
easier	O
for	O
designers	O
to	O
provide	O
their	O
users	O
with	O
semantic	B-Protocol
URLs	I-Protocol
.	O
</s>
<s>
With	O
regard	O
to	O
the	O
second	O
point	O
,	O
it	O
is	O
possible	O
to	O
use	O
client-side	O
scripting	O
,	O
or	O
to	O
write	O
standalone	O
apps	B-Application
,	O
to	O
make	O
use	O
of	O
the	O
other	O
HTTP	B-Protocol
methods	O
where	O
they	O
are	O
relevant	O
,	O
but	O
outside	O
of	O
this	O
most	O
web	B-General_Concept
forms	I-General_Concept
that	O
submit	O
or	O
alter	O
server	O
data	O
continue	O
to	O
use	O
POST	O
for	O
the	O
purpose	O
.	O
</s>
<s>
That	O
is	O
not	O
to	O
say	O
that	O
every	O
web	B-General_Concept
form	I-General_Concept
should	O
specify	O
method	O
=	O
"	O
post	O
"	O
in	O
its	O
opening	O
tag	O
.	O
</s>
<s>
There	O
are	O
times	O
when	O
HTTP	B-Protocol
GET	O
is	O
less	O
suitable	O
even	O
for	O
data	O
retrieval	O
.	O
</s>
<s>
Percent-encoding	O
of	O
reserved	O
characters	O
in	O
URLs	O
and	O
query	B-Protocol
strings	I-Protocol
can	O
significantly	O
increase	O
their	O
length	O
,	O
and	O
while	O
Apache	B-Application
HTTP	I-Application
Server	I-Application
can	O
handle	O
up	O
to	O
4,000	O
characters	O
in	O
a	O
URL	O
,	O
Microsoft	B-Application
Internet	I-Application
Explorer	I-Application
is	O
limited	O
to	O
2,048	O
characters	O
in	O
any	O
URL	O
.	O
</s>
<s>
Equally	O
,	O
HTTP	B-Protocol
GET	O
should	O
not	O
be	O
used	O
where	O
sensitive	O
information	O
,	O
such	O
as	O
usernames	O
and	O
passwords	O
,	O
have	O
to	O
be	O
submitted	O
along	O
with	O
other	O
data	O
for	O
the	O
request	O
to	O
complete	O
.	O
</s>
<s>
Even	O
if	O
HTTPS	B-Protocol
is	O
used	O
,	O
preventing	O
the	O
data	O
from	O
being	O
intercepted	O
in	O
transit	O
,	O
the	O
browser	O
history	O
and	O
the	O
web	O
server	O
's	O
logs	O
will	O
likely	O
contain	O
the	O
full	O
URL	O
in	O
plaintext	O
,	O
which	O
may	O
be	O
exposed	O
if	O
either	O
system	O
is	O
hacked	O
.	O
</s>
<s>
In	O
these	O
cases	O
,	O
HTTP	B-Protocol
POST	I-Protocol
should	O
be	O
used	O
.	O
</s>
<s>
When	O
a	O
web	O
browser	O
sends	O
a	O
POST	B-Protocol
request	I-Protocol
from	O
a	O
web	B-General_Concept
form	I-General_Concept
element	O
,	O
the	O
default	O
Internet	B-Application
media	I-Application
type	I-Application
is	O
"	O
application/x	O
-www-form-urlencoded	O
"	O
.	O
</s>
<s>
This	O
is	O
a	O
format	O
for	O
encoding	O
key-value	B-Application
pairs	I-Application
with	O
possibly	O
duplicate	O
keys	O
.	O
</s>
<s>
The	O
special	O
case	O
of	O
a	O
POST	O
to	O
the	O
same	O
page	O
that	O
the	O
form	O
belongs	O
to	O
is	O
known	O
as	O
a	O
postback	B-Application
.	O
</s>
<s>
POST	O
is	O
therefore	O
suitable	O
for	O
requests	O
which	O
change	O
the	O
state	B-Application
each	O
time	O
they	O
are	O
performed	O
,	O
for	O
example	O
submitting	O
a	O
comment	O
to	O
a	O
blog	O
post	O
or	O
voting	O
in	O
an	O
online	O
poll	O
.	O
</s>
<s>
For	O
this	O
reason	O
,	O
web	B-Application
crawlers	I-Application
such	O
as	O
search	O
engine	O
indexers	O
normally	O
use	O
the	O
GET	O
and	O
HEAD	O
methods	O
exclusively	O
,	O
to	O
prevent	O
their	O
automated	O
requests	O
from	O
performing	O
such	O
actions	O
.	O
</s>
<s>
Due	O
to	O
restrictions	O
on	O
URLs	O
,	O
the	O
query	B-Protocol
string	I-Protocol
the	O
GET	O
method	O
generates	O
may	O
become	O
very	O
long	O
,	O
especially	O
due	O
to	O
percent-encoding	O
.	O
</s>
