<s>
Blockly	B-Language
is	O
a	O
client-side	O
library	B-Library
for	O
the	O
programming	O
language	O
JavaScript	B-Language
for	O
creating	O
block-based	O
visual	B-Language
programming	I-Language
languages	I-Language
(	O
VPLs	O
)	O
and	O
editors	O
.	O
</s>
<s>
A	O
project	O
of	O
Google	B-Application
,	O
it	O
is	O
free	B-License
and	I-License
open-source	I-License
software	I-License
released	O
under	O
the	O
Apache	B-Application
License	I-Application
2.0	I-Application
.	O
</s>
<s>
It	O
typically	O
runs	O
in	O
a	O
web	B-Application
browser	I-Application
,	O
and	O
visually	O
resembles	O
the	O
language	O
Scratch	B-Language
.	O
</s>
<s>
Blockly	B-Language
uses	O
visual	O
blocks	O
that	O
link	O
together	O
to	O
make	O
writing	O
code	O
easier	O
,	O
and	O
can	O
generate	O
code	O
in	O
JavaScript	B-Language
,	O
Lua	B-Language
,	O
Dart	B-Language
,	O
Python	B-Language
,	O
or	O
PHP	B-Application
.	O
</s>
<s>
Blockly	B-Language
development	O
began	O
in	O
summer	O
2011	O
.	O
</s>
<s>
Blockly	B-Language
was	O
originally	O
designed	O
as	O
a	O
replacement	O
for	O
OpenBlocks	O
in	O
App	B-Application
Inventor	I-Application
.	O
</s>
<s>
The	O
default	O
graphical	B-Application
user	I-Application
interface	I-Application
(	O
GUI	B-Application
)	O
of	O
the	O
Blockly	B-Language
editor	O
consists	O
of	O
a	O
toolbox	O
,	O
which	O
holds	O
available	O
blocks	O
,	O
and	O
where	O
a	O
user	O
can	O
select	O
blocks	O
,	O
and	O
a	O
workspace	O
,	O
where	O
a	O
user	O
can	O
drag	O
and	O
drop	O
and	O
rearrange	O
blocks	O
.	O
</s>
<s>
Blockly	B-Language
includes	O
a	O
set	O
of	O
visual	O
blocks	O
for	O
common	O
operations	O
,	O
and	O
can	O
be	O
customized	O
by	O
adding	O
more	O
blocks	O
.	O
</s>
<s>
Definitions	O
and	O
generators	O
can	O
be	O
written	O
in	O
JavaScript	B-Language
,	O
or	O
using	O
a	O
visual	O
set	O
of	O
blocks	O
,	O
the	O
Block	O
Factory	O
,	O
which	O
allows	O
new	O
blocks	O
to	O
be	O
described	O
using	O
extant	O
visual	O
blocks	O
;	O
the	O
intent	O
is	O
to	O
make	O
creating	O
new	O
blocks	O
easier	O
.	O
</s>
<s>
Blockly	B-Language
is	O
used	O
in	O
several	O
notable	O
projects	O
,	O
including	O
:	O
</s>
<s>
MIT	O
's	O
App	B-Application
Inventor	I-Application
,	O
to	O
create	O
applications	O
for	O
Android	O
.	O
</s>
