我想用JavaScript格式化价格。我想要一个函数，它将浮点作为参数，并返回如下格式的字符串：
"$ 2,500.00"
我该怎么做？
当前回答
我想为此做出贡献：
function toMoney(amount) {
neg = amount.charAt(0);
amount = amount.replace(/\D/g, '');
amount = amount.replace(/\./g, '');
amount = amount.replace(/\-/g, '');
var numAmount = new Number(amount);
amount = numAmount.toFixed(0).replace(/./g, function(c, i, a) {
return i > 0 && c !== "," && (a.length - i) % 3 === 0 ? "." + c : c;
});
if(neg == '-')
return neg + amount;
else
return amount;
}
这允许您在一个文本框中转换数字，在该文本框中您只需要输入数字（考虑这种情况）。
这将清理一个文本框，其中只有数字，即使你粘贴了一个包含数字、字母或任何字符的字符串
<html>
<head>
<script language=="Javascript">
function isNumber(evt) {
var theEvent = evt || window.event;
var key = theEvent.keyCode || theEvent.which;
key = String.fromCharCode(key);
if (key.length == 0)
return;
var regex = /^[0-9\-\b]+$/;
if (!regex.test(key)) {
theEvent.returnValue = false;
if (theEvent.preventDefault)
theEvent.preventDefault();
}
}
function toMoney(amount) {
neg = amount.charAt(0);
amount = amount.replace(/\D/g, '');
amount = amount.replace(/\./g, '');
amount = amount.replace(/\-/g, '');
var numAmount = new Number(amount);
amount = numAmount.toFixed(0).replace(/./g, function(c, i, a) {
return i > 0 && c !== "," && (a.length - i) % 3 === 0 ? "." + c : c;
});
if(neg == '-')
return neg + amount;
else
return amount;
}
function clearText(inTxt, newTxt, outTxt) {
inTxt = inTxt.trim();
newTxt = newTxt.trim();
if(inTxt == '' || inTxt == newTxt)
return outTxt;
return inTxt;
}
function fillText(inTxt, outTxt) {
inTxt = inTxt.trim();
if(inTxt != '')
outTxt = inTxt;
return outTxt;
}
</script>
</head>
<body>
$ <input name=reca2 id=reca2 type=text value="0" onFocus="this.value = clearText(this.value, '0', '');" onblur="this.value = fillText(this.value, '0'); this.value = toMoney(this.value);" onKeyPress="isNumber(event);" style="width:80px;" />
</body>
</html>
其他回答
这里有一些解决方案，都通过了测试套件。包括测试套件和基准测试。如果你想复制和粘贴来测试，试试这个要点。
方法0（RegExp）
它是基于VisioN的答案，但如果没有小数点，它会修复。
if (typeof Number.prototype.format === 'undefined') {
Number.prototype.format = function (precision) {
if (!isFinite(this)) {
return this.toString();
}
var a = this.toFixed(precision).split('.');
a[0] = a[0].replace(/\d(?=(\d{3})+$)/g, '$&,');
return a.join('.');
}
}
方法1
if (typeof Number.prototype.format === 'undefined') {
Number.prototype.format = function (precision) {
if (!isFinite(this)) {
return this.toString();
}
var a = this.toFixed(precision).split('.'),
// Skip the '-' sign
head = Number(this < 0);
// Skip the digits that's before the first thousands separator
head += (a[0].length - head) % 3 || 3;
a[0] = a[0].slice(0, head) + a[0].slice(head).replace(/\d{3}/g, ',$&');
return a.join('.');
};
}
方法2（拆分到阵列）
if (typeof Number.prototype.format === 'undefined') {
Number.prototype.format = function (precision) {
if (!isFinite(this)) {
return this.toString();
}
var a = this.toFixed(precision).split('.');
a[0] = a[0]
.split('').reverse().join('')
.replace(/\d{3}(?=\d)/g, '$&,')
.split('').reverse().join('');
return a.join('.');
};
}
方法3（循环）
if (typeof Number.prototype.format === 'undefined') {
Number.prototype.format = function (precision) {
if (!isFinite(this)) {
return this.toString();
}
var a = this.toFixed(precision).split('');
a.push('.');
var i = a.indexOf('.') - 3;
while (i > 0 && a[i-1] !== '-') {
a.splice(i, 0, ',');
i -= 3;
}
a.pop();
return a.join('');
};
}
用法示例
console.log('======== Demo ========')
console.log(
(1234567).format(0),
(1234.56).format(2),
(-1234.56).format(0)
);
var n = 0;
for (var i=1; i<20; i++) {
n = (n * 10) + (i % 10)/100;
console.log(n.format(2), (-n).format(2));
}
分离器
如果我们需要自定义千位分隔符或小数分隔符，请使用replace（）：
123456.78.format(2).replace(',', ' ').replace('.', ' ');
测试套件
function assertEqual(a, b) {
if (a !== b) {
throw a + ' !== ' + b;
}
}
function test(format_function) {
console.log(format_function);
assertEqual('NaN', format_function.call(NaN, 0))
assertEqual('Infinity', format_function.call(Infinity, 0))
assertEqual('-Infinity', format_function.call(-Infinity, 0))
assertEqual('0', format_function.call(0, 0))
assertEqual('0.00', format_function.call(0, 2))
assertEqual('1', format_function.call(1, 0))
assertEqual('-1', format_function.call(-1, 0))
// Decimal padding
assertEqual('1.00', format_function.call(1, 2))
assertEqual('-1.00', format_function.call(-1, 2))
// Decimal rounding
assertEqual('0.12', format_function.call(0.123456, 2))
assertEqual('0.1235', format_function.call(0.123456, 4))
assertEqual('-0.12', format_function.call(-0.123456, 2))
assertEqual('-0.1235', format_function.call(-0.123456, 4))
// Thousands separator
assertEqual('1,234', format_function.call(1234.123456, 0))
assertEqual('12,345', format_function.call(12345.123456, 0))
assertEqual('123,456', format_function.call(123456.123456, 0))
assertEqual('1,234,567', format_function.call(1234567.123456, 0))
assertEqual('12,345,678', format_function.call(12345678.123456, 0))
assertEqual('123,456,789', format_function.call(123456789.123456, 0))
assertEqual('-1,234', format_function.call(-1234.123456, 0))
assertEqual('-12,345', format_function.call(-12345.123456, 0))
assertEqual('-123,456', format_function.call(-123456.123456, 0))
assertEqual('-1,234,567', format_function.call(-1234567.123456, 0))
assertEqual('-12,345,678', format_function.call(-12345678.123456, 0))
assertEqual('-123,456,789', format_function.call(-123456789.123456, 0))
// Thousands separator and decimal
assertEqual('1,234.12', format_function.call(1234.123456, 2))
assertEqual('12,345.12', format_function.call(12345.123456, 2))
assertEqual('123,456.12', format_function.call(123456.123456, 2))
assertEqual('1,234,567.12', format_function.call(1234567.123456, 2))
assertEqual('12,345,678.12', format_function.call(12345678.123456, 2))
assertEqual('123,456,789.12', format_function.call(123456789.123456, 2))
assertEqual('-1,234.12', format_function.call(-1234.123456, 2))
assertEqual('-12,345.12', format_function.call(-12345.123456, 2))
assertEqual('-123,456.12', format_function.call(-123456.123456, 2))
assertEqual('-1,234,567.12', format_function.call(-1234567.123456, 2))
assertEqual('-12,345,678.12', format_function.call(-12345678.123456, 2))
assertEqual('-123,456,789.12', format_function.call(-123456789.123456, 2))
}
console.log('======== Testing ========');
test(Number.prototype.format);
test(Number.prototype.format1);
test(Number.prototype.format2);
test(Number.prototype.format3);
基准
function benchmark(f) {
var start = new Date().getTime();
f();
return new Date().getTime() - start;
}
function benchmark_format(f) {
console.log(f);
time = benchmark(function () {
for (var i = 0; i < 100000; i++) {
f.call(123456789, 0);
f.call(123456789, 2);
}
});
console.log(time.format(0) + 'ms');
}
// If not using async, the browser will stop responding while running.
// This will create a new thread to benchmark
async = [];
function next() {
setTimeout(function () {
f = async.shift();
f && f();
next();
}, 10);
}
console.log('======== Benchmark ========');
async.push(function () { benchmark_format(Number.prototype.format); });
next();
PatrickDesjardins的回答看起来不错，但我更喜欢简单的JavaScript代码。下面是我刚刚编写的一个函数，用于输入一个数字并以货币格式返回（减去美元符号）：
// Format numbers to two decimals with commas
function formatDollar(num) {
var p = num.toFixed(2).split(".");
var chars = p[0].split("").reverse();
var newstr = '';
var count = 0;
for (x in chars) {
count++;
if(count%3 == 1 && count != 1) {
newstr = chars[x] + ',' + newstr;
} else {
newstr = chars[x] + newstr;
}
}
return newstr + "." + p[1];
}
String.prototype.toPrice = function () {
var v;
if (/^\d+(,\d+)$/.test(this))
v = this.replace(/,/, '.');
else if (/^\d+((,\d{3})*(\.\d+)?)?$/.test(this))
v = this.replace(/,/g, "");
else if (/^\d+((.\d{3})*(,\d+)?)?$/.test(this))
v = this.replace(/\./g, "").replace(/,/, ".");
var x = parseFloat(v).toFixed(2).toString().split("."),
x1 = x[0],
x2 = ((x.length == 2) ? "." + x[1] : ".00"),
exp = /^([0-9]+)(\d{3})/;
while (exp.test(x1))
x1 = x1.replace(exp, "$1" + "," + "$2");
return x1 + x2;
}
alert("123123".toPrice()); //123,123.00
alert("123123,316".toPrice()); //123,123.32
alert("12,312,313.33213".toPrice()); //12,312,313.33
alert("123.312.321,32132".toPrice()); //123,312,321.32
我使用库Globalize（来自Microsoft）：
这是一个很好的项目，可以本地化数字、货币和日期，并根据用户的语言环境以正确的方式自动格式化它们。。。尽管它应该是一个jQuery扩展，但它目前是一个100%独立的库。我建议大家都试试看！：）
Patrick Desjardins（前Daok）的例子对我很有用。如果有人感兴趣，我将其移植到CoffeeScript。
Number.prototype.toMoney = (decimals = 2, decimal_separator = ".", thousands_separator = ",") ->
n = this
c = if isNaN(decimals) then 2 else Math.abs decimals
sign = if n < 0 then "-" else ""
i = parseInt(n = Math.abs(n).toFixed(c)) + ''
j = if (j = i.length) > 3 then j % 3 else 0
x = if j then i.substr(0, j) + thousands_separator else ''
y = i.substr(j).replace(/(\d{3})(?=\d)/g, "$1" + thousands_separator)
z = if c then decimal_separator + Math.abs(n - i).toFixed(c).slice(2) else ''
sign + x + y + z
