JS浮動小数点の値は正確に計算されます。
14100 ワード
from:http://rockyee.iteye.com/blog/891538
テスト：
alert（Number（9.13-9.02）；
alert(Number(9.11-9.02).toFixed(2)；
1
Number.prototype.toFixed
=
function
(scale){
2
var
s
=
this
+
""
;
3
if
(
!
scale) scale
=
0
;
4
if
(s.indexOf(
"
.
"
)
==
-
1
) s
+=
"
.
"
;
5
s
+=
new
Array(scale
+
1
).join(
"
0
"
);
6
if
(
new
RegExp(
"
^(-|\\+)?(\\d+(\\.\\d{0,
"
+
(scale
+
1
)
+
"
})?)\\d*$
"
).test(s))
7
{
8
var
s
=
"
0
"
+
RegExp.$
2
, pm
=
RegExp.$
1
, a
=
RegExp.$
3
.length, b
=
true
;
9
if
(a
==
scale
+
2
)
10
{
11
a
=
s.match(
/
\d
/
g);
12
if
(parseInt(a[a.length
-
1
])
>
4
)
13
{
14
for
(
var
i
=
a.length
-
2
; i
>=
0
; i
--
)
15
{
16
a[i]
=
parseInt(a[i])
+
1
;
17
if
(a[i]
==
10
)
18
{
19
a[i]
=
0
;
20
b
=
i
!=
1
;
21
}
22
else
23
break
;
24
}
25
}
26
s
=
a.join(
""
).replace(
new
RegExp(
"
(\\d+)(\\d{
"
+
scale
+
"
})\\d$
"
),
"
$1.$2
"
);
27
}
28
if
(b) s
=
s.substr(
1
);
29
return
(pm
+
s).replace(
/
\.$
/
,
""
);
30
}
31
return
this
+
""
;
32
}
テスト：
alert（Number（9.13-9.02）；
alert(Number(9.11-9.02).toFixed(2)；