JavaScript jsは正確で、小数点以下の方法を保留します.
4872 ワード
//
// : , 2
function toDecimal(x) {
var f = parseFloat(x);
if (isNaN(f)) {
return;
}
f = Math.round(x*100)/100;
return f;
}
// 2 , :2, 2 00. 2.00
function toDecimal2(x) {
var f = parseFloat(x);
if (isNaN(f)) {
return false;
}
var f = Math.round(x*100)/100;
var s = f.toString();
var rs = s.indexOf('.');
if (rs < 0) {
rs = s.length;
s += '.';
}
while (s.length <= rs + 2) {
s += '0';
}
return s;
}
function fomatFloat(src,pos){
return Math.round(src*Math.pow(10, pos))/Math.pow(10, pos);
}
//
alert(" 2 :" + toDecimal(3.14159267));
alert(" 2 :" + toDecimal2(3.14159267));
alert(" 2 :" + toDecimal(3.14559267));
alert(" 2 :" + toDecimal2(3.15159267));
alert(" 2 :" + fomatFloat(3.14559267, 2));
alert(" 1 :" + fomatFloat(3.15159267, 1));
//
alert(" 2 :" + 1000.003.toFixed(2));
alert(" 1 :" + 1000.08.toFixed(1));
alert(" 1 :" + 1000.04.toFixed(1));
alert(" 1 :" + 1000.05.toFixed(1));
//
alert(3.1415.toExponential(2));
alert(3.1455.toExponential(2));
alert(3.1445.toExponential(2));
alert(3.1465.toExponential(2));
alert(3.1665.toExponential(1));
// n , n
alert(" 2 " + 3.1415.toPrecision(2));
alert(" 3 " + 3.1465.toPrecision(3));
alert(" 2 " + 3.1415.toPrecision(2));
alert(" 2 " + 3.1455.toPrecision(2));
alert(" 5 " + 3.141592679287.toPrecision(5));
</script>