<s>
Velocity	O
is	O
a	O
cross-platform	B-Operating_System
JavaScript	B-Language
library	I-Language
designed	O
to	O
simplify	O
the	O
client-side	O
scripting	O
of	O
website	O
animation	O
.	O
</s>
<s>
Velocity	O
is	O
free	B-Application
,	I-Application
open-source	I-Application
software	O
licensed	O
under	O
the	B-License
MIT	I-License
License	I-License
.	O
</s>
<s>
Velocity	O
's	O
syntax	O
is	O
designed	O
to	O
make	O
it	O
easier	O
to	O
create	O
complex	O
animations	O
for	O
HTML	B-Language
and	O
SVG	B-Application
elements	O
.	O
</s>
<s>
In	O
addition	O
to	O
its	O
workflow	O
benefits	O
,	O
Velocity	O
provides	O
animation	O
performance	O
that	O
is	O
competitive	O
with	O
CSS-based	O
animation	O
.	O
</s>
<s>
Velocity	O
achieves	O
its	O
performance	O
by	O
maintaining	O
an	O
internal	O
cache	O
of	O
animation	O
states	O
and	O
minimizing	O
"	O
layout	O
thrashing	B-General_Concept
,	O
"	O
the	O
undesirable	O
behavior	O
that	O
web	B-Application
browsers	I-Application
undergo	O
when	O
visually	O
updating	O
at	O
a	O
fast	O
rate	O
.	O
</s>
<s>
Its	O
broad	O
browser	B-Application
and	O
device	O
support	O
make	O
it	O
ideal	O
for	O
large	O
enterprise	O
distributions	O
that	O
must	O
support	O
low-powered	O
devices	O
.	O
</s>
<s>
Velocity	O
is	O
used	O
to	O
power	O
the	O
user	O
interfaces	O
of	O
many	O
notable	O
websites	O
,	O
including	O
Uber	B-Application
,	O
Samsung	B-Application
,	O
WhatsApp	B-Application
,	O
Tumblr	B-Application
,	O
HTC	B-Application
,	O
Mazda	O
,	O
and	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
It	O
is	O
one	O
of	O
the	O
most	O
favorited	O
projects	O
on	O
the	O
code	O
hosting	O
service	O
GitHub	B-Application
.	O
</s>
<s>
Velocity	O
supports	O
all	O
major	O
desktop	O
browsers	B-Application
(	O
Firefox	B-Application
,	O
Google	B-Application
Chrome	I-Application
,	O
and	O
Safari	B-Application
)	O
plus	O
the	O
iOS	B-Application
and	O
Android	B-Application
mobile	I-Application
operating	O
systems	O
.	O
</s>
<s>
Its	O
support	O
extends	O
as	O
far	O
back	O
as	O
Internet	B-Application
Explorer	I-Application
8	O
and	O
Android	B-Application
2.3	O
.	O
</s>
<s>
The	O
Velocity	O
library	O
is	O
a	O
single	O
JavaScript	B-Language
file	O
containing	O
all	O
of	O
its	O
core	O
functions	O
.	O
</s>
<s>
It	O
can	O
be	O
included	O
within	O
a	O
web	O
page	O
by	O
linking	O
to	O
a	O
local	O
copy	O
or	O
to	O
one	O
of	O
the	O
many	O
copies	O
available	O
from	O
public	O
servers	O
,	O
including	O
MaxCDN	O
's	O
jsDelivr	B-Application
or	O
Cloudflare	B-Application
's	O
.	O
</s>
<s>
It	O
is	O
recommended	O
to	O
always	O
use	O
HTTPS	B-Protocol
for	O
resources	O
but	O
this	O
can	O
be	O
replaced	O
with	O
//	O
to	O
make	O
use	O
of	O
protocol	O
relative	O
URLs	O
.	O
</s>
<s>
The	O
$	O
.Velocity	O
function	O
,	O
which	O
is	O
a	O
factory	B-Language
method	I-Language
extended	O
from	O
the	O
jQuery	B-Language
root	O
object	O
.	O
</s>
<s>
This	O
method	O
animates	O
raw	O
DOM	B-General_Concept
elements	O
instead	O
of	O
jQuery-wrapped	O
elements	O
.	O
</s>
<s>
This	O
is	O
the	O
style	O
employed	O
when	O
using	O
Velocity	O
without	O
jQuery	B-Language
on	O
the	O
page	O
.	O
</s>
<s>
This	O
is	O
the	O
style	O
used	O
for	O
animating	O
jQuery	B-Language
element	O
objects	O
when	O
jQuery	B-Language
is	O
present	O
on	O
the	O
page	O
.	O
</s>
<s>
Animation	O
calls	O
in	O
Velocity	O
consist	O
of	O
supplying	O
the	O
desired	O
element(s )	O
to	O
animate	O
,	O
an	O
animation	O
property	O
map	O
to	O
specify	O
the	O
CSS	B-Language
properties	O
to	O
be	O
animated	O
,	O
and	O
an	O
optional	O
options	O
object	O
to	O
specify	O
animation	O
settings	O
(	O
e.g.	O
</s>
<s>
scroll	O
or	O
reverse	O
)	O
or	O
an	O
object	O
consisting	O
of	O
CSS	B-Language
properties	O
to	O
be	O
animated	O
:	O
</s>
<s>
Creating	O
a	O
series	O
of	O
consecutive	O
animation	O
calls	O
in	O
Velocity	O
consists	O
of	O
placing	O
velocity( )	O
calls	O
back-to-back	O
on	O
the	O
target	O
jQuery	B-Language
element	O
object	O
:	O
</s>
<s>
Scrolling	O
in	O
Velocity	O
consists	O
of	O
passing	O
in	O
"	O
scroll	O
"	O
as	O
Velocity	O
's	O
first	O
argument	O
—	O
in	O
place	O
of	O
the	O
typical	O
CSS	B-Language
properties	O
map	O
:	O
</s>
<s>
The	O
browser	B-Application
will	O
subsequently	O
scroll	O
down	O
to	O
the	O
top	O
edge	O
of	O
the	O
element	O
that	O
Velocity	O
was	O
invoked	O
on	O
.	O
</s>
<s>
Velocity	O
was	O
developed	O
by	O
Julian	O
Shapiro	O
to	O
address	O
a	O
lack	O
of	O
performant	O
and	O
designer-oriented	O
JavaScript	B-Language
animation	O
libraries	O
.	O
</s>
<s>
Stripe	B-Application
,	O
a	O
popular	O
web	O
developer-focused	O
Internet	B-Protocol
technology	I-Protocol
company	O
sponsored	O
Shapiro	O
on	O
a	O
grant	O
to	O
help	O
provide	O
the	O
financial	O
resources	O
necessary	O
to	O
continue	O
full-time	O
development	O
on	O
Velocity	O
.	O
</s>
<s>
The	O
high	O
performance	O
of	O
Velocity	O
's	O
internal	O
animation	O
engine	O
helped	O
to	O
repopularize	O
JavaScript-based	O
web	O
animation	O
,	O
which	O
had	O
previously	O
fallen	O
out	O
of	O
favor	O
for	O
CSS-based	O
animation	O
due	O
to	O
its	O
speed	O
advantages	O
over	O
older	O
JavaScript	B-Language
libraries	I-Language
that	O
lacked	O
a	O
focus	O
on	O
animation	O
.	O
</s>
<s>
In	O
September	O
2014	O
,	O
Shapiro	O
released	O
Velocity	O
Motion	O
Designer	O
,	O
a	O
tool	O
for	O
designing	O
animations	O
on	O
live	O
production	O
websites	O
that	O
allowed	O
for	O
real-time	O
exporting	O
of	O
the	O
generated	O
animation	O
code	O
for	O
subsequent	O
use	O
within	O
an	O
IDE	B-Application
.	O
</s>
<s>
In	O
March	O
2015	O
,	O
Peachpit	O
published	O
Shapiro	O
's	O
Web	O
Animation	O
using	O
JavaScript	B-Language
book	O
,	O
which	O
teaches	O
both	O
the	O
beginning	O
and	O
advanced	O
principles	O
of	O
developing	O
web	O
animations	O
using	O
Velocity	O
.	O
</s>
