<s>
Caja	B-Language
(	O
pronounced	O
)	O
was	O
a	O
Google	B-Application
project	O
for	O
sanitizing	B-General_Concept
third	I-General_Concept
party	I-General_Concept
HTML	I-General_Concept
,	O
CSS	B-Language
and	O
JavaScript	B-Language
.	O
</s>
<s>
On	O
January	O
31	O
,	O
2021	O
,	O
Google	B-Application
archived	O
the	O
project	O
due	O
to	O
known	O
vulnerabilities	O
and	O
lack	O
of	O
maintenance	O
to	O
keep	O
up	O
with	O
the	O
latest	O
web	O
security	O
research	O
,	O
recommending	O
instead	O
the	O
Closure	B-Language
toolkit	I-Language
.	O
</s>
<s>
Caja	B-Language
was	O
designed	O
by	O
Google	B-Application
research	O
scientist	O
Mark	O
S	O
.	O
Miller	O
in	O
2008	O
as	O
a	O
JavaScript	B-Language
implementation	O
for	O
"	O
virtual	O
iframes	O
"	O
based	O
on	O
the	O
principles	O
of	O
object-capabilities	O
.	O
</s>
<s>
It	O
would	O
take	O
JavaScript	B-Language
(	O
technically	O
,	O
ECMAScript	O
5	O
strict	O
mode	O
code	O
)	O
,	O
HTML	B-Language
,	O
and	O
CSS	B-Language
input	O
and	O
rewrite	O
it	O
into	O
a	O
safe	O
subset	O
of	O
HTML	B-Language
and	O
CSS	B-Language
,	O
plus	O
a	O
single	O
JavaScript	B-Language
function	O
with	O
no	O
free	O
variables	O
.	O
</s>
<s>
Instead	O
of	O
giving	O
direct	O
references	O
to	O
DOM	B-General_Concept
objects	O
,	O
the	O
host	O
page	O
typically	O
gives	O
references	O
to	O
wrappers	O
that	O
sanitize	O
HTML	B-Language
,	O
proxy	O
URLs	O
,	O
and	O
prevent	O
redirecting	O
the	O
page	O
;	O
this	O
allowed	O
Caja	B-Language
to	O
prevent	O
certain	O
phishing	O
and	O
cross-site	O
scripting	O
attacks	O
,	O
and	O
prevent	O
downloading	O
malware	O
.	O
</s>
<s>
The	O
word	O
"	O
caja	B-Language
"	O
is	O
Spanish	O
for	O
"	O
box	O
"	O
or	O
"	O
safe	O
"	O
(	O
as	O
in	O
a	O
bank	O
)	O
,	O
the	O
idea	O
being	O
that	O
Caja	B-Language
could	O
safely	O
contain	O
JavaScript	B-Language
programs	O
as	O
well	O
as	O
being	O
a	O
capabilities-based	O
JavaScript	B-Language
.	O
</s>
<s>
Caja	B-Language
was	O
used	O
by	O
Google	B-Application
in	O
its	O
Google	B-Application
Apps	I-Application
Script	I-Application
products	O
.	O
</s>
<s>
In	O
2008	O
MySpace	B-Application
and	O
Yahoo	B-Application
!	I-Application
</s>
<s>
had	O
both	O
deployed	O
a	O
very	O
early	O
version	O
of	O
Caja	B-Language
.	O
</s>
