<s>
HTML	B-General_Concept
attributes	I-General_Concept
are	O
special	O
words	O
used	O
inside	O
the	O
opening	O
tag	B-General_Concept
to	O
control	O
the	O
element	O
's	O
behaviour	O
.	O
</s>
<s>
HTML	B-General_Concept
attributes	I-General_Concept
are	O
a	O
modifier	O
of	O
a	O
HTML	B-General_Concept
element	I-General_Concept
type	O
.	O
</s>
<s>
In	O
HTML	O
syntax	O
,	O
an	O
attribute	O
is	O
added	O
to	O
a	O
HTML	B-General_Concept
start	I-General_Concept
tag	I-General_Concept
.	O
</s>
<s>
Several	O
basic	O
attributes	O
types	O
have	O
been	O
recognized	O
,	O
including	O
:	O
(	O
1	O
)	O
required	O
attributes	O
,	O
needed	O
by	O
a	O
particular	O
element	O
type	O
for	O
that	O
element	O
type	O
to	O
function	O
correctly	O
;	O
(	O
2	O
)	O
optional	O
attributes	O
,	O
used	O
to	O
modify	O
the	O
default	O
functionality	O
of	O
an	O
element	O
type	O
;	O
(	O
3	O
)	O
standard	O
attributes	O
,	O
supported	O
by	O
many	O
element	O
types	O
;	O
and	O
(	O
4	O
)	O
event	O
attributes	O
,	O
used	O
to	O
cause	O
element	O
types	O
to	O
specify	O
scripts	B-Language
to	O
be	O
run	O
under	O
specific	O
circumstances	O
.	O
</s>
<s>
HTML	B-General_Concept
attributes	I-General_Concept
generally	O
appear	O
as	O
name	B-Application
–	I-Application
value	I-Application
pairs	I-Application
,	O
separated	O
by	O
=	O
,	O
and	O
are	O
written	O
within	O
the	O
start	O
tag	B-General_Concept
of	O
an	O
element	O
,	O
after	O
the	O
element	O
's	O
name	O
:	O
</s>
<s>
Where	O
element	O
names	O
the	O
HTML	B-General_Concept
element	I-General_Concept
type	O
,	O
and	O
attribute	O
is	O
the	O
name	O
of	O
the	O
attribute	O
,	O
set	O
to	O
the	O
provided	O
value	O
.	O
</s>
<s>
Although	O
most	O
attributes	O
are	O
provided	O
as	O
paired	O
names	O
and	O
values	O
,	O
some	O
affect	O
the	O
element	O
simply	O
by	O
their	O
presence	O
in	O
the	O
start	O
tag	B-General_Concept
of	O
the	O
element	O
(	O
like	O
the	O
ismap	O
attribute	O
for	O
the	O
img	O
element	O
)	O
.	O
</s>
<s>
Usually	O
,	O
HTML	B-General_Concept
elements	I-General_Concept
can	O
take	O
any	O
of	O
several	O
most	O
common	O
standard	O
attributes	O
(	O
See	O
the	O
complete	O
list	O
)	O
:	O
</s>
<s>
This	O
can	O
be	O
used	O
as	O
CSS	O
selector	O
to	O
provide	O
presentational	O
properties	O
,	O
by	O
browsers	O
to	O
focus	O
attention	O
on	O
the	O
specific	O
element	O
,	O
or	O
by	O
scripts	B-Language
to	O
alter	O
the	O
contents	O
or	O
presentation	O
of	O
an	O
element	O
.	O
</s>
<s>
Semantically	O
,	O
for	O
example	O
,	O
classes	O
are	O
used	O
in	O
microformats	B-General_Concept
.	O
</s>
<s>
The	O
style	O
attribute	O
can	O
be	O
used	O
on	O
any	O
HTML	B-General_Concept
element	I-General_Concept
(	O
it	O
will	O
validate	O
on	O
any	O
HTML	B-General_Concept
element	I-General_Concept
;	O
however	O
,	O
it	O
is	O
not	O
necessarily	O
useful	O
)	O
.	O
</s>
<s>
While	O
the	O
standard	O
attributes	O
can	O
be	O
applied	O
to	O
most	O
HTML	B-General_Concept
elements	I-General_Concept
.	O
</s>
<s>
Event	O
attributes	O
,	O
added	O
in	O
HTML	O
version	O
4	O
,	O
allow	O
an	O
element	O
to	O
specify	O
scripts	B-Language
to	O
be	O
run	O
under	O
specific	O
circumstances	O
.	O
</s>
<s>
hreflang	B-General_Concept
—	O
Language	O
code	O
of	O
the	O
linked	O
document	O
.	O
</s>
<s>
Values	O
:	O
col	O
,	O
colgroup	O
,	O
row	O
,	O
rowgroup	B-General_Concept
.	O
</s>
<s>
Event	O
attributes	O
,	O
added	O
in	O
HTML	O
version	O
4	O
,	O
allow	O
an	O
element	O
to	O
specify	O
scripts	B-Language
to	O
be	O
run	O
under	O
specific	O
circumstances	O
.	O
</s>
