以下是五个有用的JS数字格式化函数
1. 四舍五入
下面两个函数都能对浮点数进行四舍五入，保留小数点后两位。
2. 给数字添加逗号
每三位数字添加一个逗号，方便阅读
3. 类似PHP的 number_format 功能
这个函数可以添加分隔逗号或者进行四舍五入。
4. 添加序数词
给数字添加”st, nd, rd, th”等序数词。
5. 从字符串中移除非数字字符
[js]
// 四舍五入
/** 下面两个函数都能对浮点数进行四舍五入，保留小数点后两位 **/
function CurrencyFormatted(amount) {
var i = parseFloat(amount);
if(isNaN(i)) { i = 0.00; }
var minus = ”;
if(i < 0) { minus = ‘-‘; }
i = Math.abs(i);
i = parseInt((i + .005) * 100);
i = i / 100;
s = new String(i);
if(s.indexOf(‘.’) < 0) { s += ‘.00’; }
if(s.indexOf(‘.’) == (s.length – 2)) { s += ‘0’; }
s = minus + s;
return s;
}
/**
* Usage: CurrencyFormatted(12345.678);
* result: 12345.68
**/
function format_number(pnumber,decimals){
if (isNaN(pnumber)) { return 0};
if (pnumber==”) { return 0};
var snum = new String(pnumber);
var sec = snum.split(‘.’);
var whole = parseFloat(sec[0]);
var result = ”;
if(sec.length > 1){
var dec = new String(sec[1]);
dec = String(parseFloat(sec[1])/Math.pow(10,(dec.length – decimals)));
dec = String(whole + Math.round(parseFloat(dec))/Math.pow(10,decimals));
var dot = dec.indexOf(‘.’);
if(dot == -1){
dec += ‘.’;
dot = dec.indexOf(‘.’);
}
while(dec.length <= dot + decimals) { dec += ‘0’; }
result = dec;
} else{
var dot;
var dec = new String(whole);
dec += ‘.’;
dot = dec.indexOf(‘.’);
while(dec.length <= dot + decimals) { dec += ‘0’; }
result = dec;
}
return result;
}
/**
* Usage: format_number(12345.678, 2);
* result: 12345.68
**/
//给数字添加逗号
/** 每三位数字添加一个逗号，方便阅读 **/
function CommaFormatted(amount) {
var delimiter = ","; // replace comma if desired
amount = new String(amount);
var a = amount.split(‘.’,2)
var d = a[1];
var i = parseInt(a[0]);
if(isNaN(i)) { return ”; }
var minus = ”;
if(i < 0) { minus = ‘-‘; }
i = Math.abs(i);
var n = new String(i);
var a = [];
while(n.length > 3)
{
var nn = n.substr(n.length-3);
a.unshift(nn);
n = n.substr(0,n.length-3);
}
if(n.length > 0) { a.unshift(n); }
n = a.join(delimiter);
if(d.length < 1) { amount = n; }
else { amount = n + ‘.’ + d; }
amount = minus + amount;
return amount;
}
/**
* Usage: CommaFormatted(12345678);
* result: 12,345,678
**/
function addCommas(nStr) {
nStr += ”;
var x = nStr.split(‘.’);
var x1 = x[0];
var x2 = x.length >; 1 ? ‘.’ + x[1] : ”;
var rgx = /(d+)(d{3})/;
while (rgx.test(x1)) {
x1 = x1.replace(rgx, ‘$1’ + ‘,’ + ‘$2’);
}
return x1 + x2;
}
/**
* Usage: addCommas(12345678);
* result: 12,345,678
**/
//类似PHP的 number_format 功能
/** 这个函数可以添加分隔逗号或者进行四舍五入。 **/
function number_format (number, decimals, dec_point, thousands_sep) {
number = (number + ”).replace(/[^0-9+-Ee.]/g, ”);
var n = !isFinite(+number) ? 0 : +number,
prec = !isFinite(+decimals) ? 0 : Math.abs(decimals),
sep = (typeof thousands_sep === ‘undefined’) ? ‘,’ : thousands_sep,
dec = (typeof dec_point === ‘undefined’) ? ‘.’ : dec_point,
s = ”,
toFixedFix = function (n, prec) {
var k = Math.pow(10, prec);
return ” + Math.round(n * k) / k;
};
// Fix for IE parseFloat(0.55).toFixed(0) = 0;
s = (prec ? toFixedFix(n, prec) : ” + Math.round(n)).split(‘.’);
if (s[0].length > 3) {
s[0] = s[0].replace(/B(?=(?:d{3})+(?!d))/g, sep);
}
if ((s[1] || ”).length < prec) {
s[1] = s[1] || ”;
s[1] += new Array(prec – s[1].length + 1).join(‘0’);
}
return s.join(dec);
}
/**
* Usage: number_format(123456.789, 2, ‘.’, ‘,’);
* result: 123,456.79
**/
//添加序数词
/** 给数字添加"st, nd, rd, th"等序数词。 **/
Number.prototype.toOrdinal = function() {
var n = this % 100;
var suffix = [‘th’, ‘st’, ‘nd’, ‘rd’, ‘th’];
var ord = n < 21 ? (n < 4 ? suffix[n] : suffix[0]) : (n % 10 > 4 ? suffix[0] : suffix[n % 10]);
return this + ord;
}
/*
* Usage:
* var myNumOld = 23
* var myNumNew = myNumOld.toOrdinal()
* Result: 23rd
*/
[/js]