numObject.toRound([fractionDigits])numObject:数值
fractionDigits:可选项,需精确到的小数点后位数<SCRIPT LANGUAGE="JavaScript">
Number.prototype.toRound = function(digits){
if (arguments.length == 0)
digits = 0; if (/^([1-9]+\d*|0)$/.test(digits))
{
var factor = Math.pow(10, digits);
return Math.round(factor * this)/factor;
}else
return NaN;
}var a = 2.34953712;
alert(a.toRound(3));
alert(2.34543712.toRound(5));
alert(a.toRound())
</SCRIPT>
fractionDigits:可选项,需精确到的小数点后位数<SCRIPT LANGUAGE="JavaScript">
Number.prototype.toRound = function(digits){
if (arguments.length == 0)
digits = 0; if (/^([1-9]+\d*|0)$/.test(digits))
{
var factor = Math.pow(10, digits);
return Math.round(factor * this)/factor;
}else
return NaN;
}var a = 2.34953712;
alert(a.toRound(3));
alert(2.34543712.toRound(5));
alert(a.toRound())
</SCRIPT>
<script>
function f(num){
var numstr=String(num+0.005);
return numstr.substring(0,numstr.indexOf(".")+3);
}
alert(f(32.216021548));
</script>
应为 alert(32.210021548.toFixed(2));
function test_math(str)
{var reg=/^(\d+\.\d{2}$)/;
if (!reg.test(str))
{alert("您输入的数字有误!");
}
}
</script>
function test_math(str)
{var reg=/^(\d+\.\d{2}$)/;
if (!reg.test(str))
{alert("您输入的数字有误!");
}
}
</script>