<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title> JS 浮点计算精度问题 </title>
</head>
<body>
<script type="text/javascript">
<!--
function accDiv(arg1, arg2) {
var t1 = 0, t2 = 0, t3 = 0, r1, r2;
try { t1 = arg1.toString().split(".")[1].length } catch (e) { }
try { t2 = arg2.toString().split(".")[1].length } catch (e) { }
r1 = Number(arg1.toString().replace(".", ""))
r2 = Number(arg2.toString().replace(".", ""))
if (r2 == 0)
return 0;
var result = String(r1 / r2);
try { t3 = result.toString().split(".")[1].length } catch (e) { }
var index = t2 - t1 - t3;
if (index < 0) {
result = result.replace(".", "");
while (result.length <= Math.abs(index)) {
result = '0' + result;
}
var start = result.substring(0, result.length + index);
var end = result.substring(result.length + index, result.length);
result = start + '.' + end;
return Number(result);
}
else if (index > 0) {
result = result.replace(".", "");
while (result.length <= Math.abs(index)) {
result += '0';
}
return Number(result);
}
else return Number(result.replace(".", ""));
}
//给Number类型增加一个div方法，调用起来更加方便。
Number.prototype.div = function (arg) {
/// <summary>
/// 除法
/// </summary>
return accDiv(this, arg);
}
function accMul(arg1, arg2) {
var m = 0, s1 = arg1.toString(), s2 = arg2.toString();
try { m += s1.split(".")[1].length } catch (e) { }
try { m += s2.split(".")[1].length } catch (e) { }
return Number(s1.replace(".", "")) * Number(s2.replace(".", "")) / Math.pow(10, m)
}
Number.prototype.mul = function (arg) {
/// <summary>
/// 乘法
/// </summary>
return accMul(arg, this);
}
function accAdd(arg1, arg2) {
var r1, r2, m, c;
try { r1 = arg1.toString().split(".")[1].length } catch (e) { r1 = 0 }
try { r2 = arg2.toString().split(".")[1].length } catch (e) { r2 = 0 }
c = Math.abs(r1 - r2);
m = Math.pow(10, Math.max(r1, r2))
if (c > 0) {
var cm = Math.pow(10, c);
if (r1 > r2) {
arg1 = Number(arg1.toString().replace(".", ""));
arg2 = Number(arg2.toString().replace(".", "")) * cm;
}
else {
arg1 = Number(arg1.toString().replace(".", "")) * cm;
arg2 = Number(arg2.toString().replace(".", ""));
}
}
else {
arg1 = Number(arg1.toString().replace(".", ""));
arg2 = Number(arg2.toString().replace(".", ""));
}
return (arg1 + arg2) / m
}
Number.prototype.add = function (arg) {
/// <summary>
/// 加法
/// </summary>
return accAdd(arg, this);
}
// 除法，两种写法，都可以，其他一样
alert(accDiv(2.1,10));
alert(2.1.div(10));
// 乘法
alert(accMul(2.1,0.01));
//-->
</script>
</body>
</html>
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