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
我主要基于VisionN的回答：
function format (val) {
val = (+val).toLocaleString();
val = (+val).toFixed(2);
val += "";
return val.replace(/(\d)(?=(\d{3})+(?:\.\d+)?$)/g, "$1" + format.thousands);
}
(function (isUS) {
format.decimal = isUS ? "." : ",";
format.thousands = isUS ? "," : ".";
}(("" + (+(0.00).toLocaleString()).toFixed(2)).indexOf(".") > 0));
我用输入进行了测试：
[ ""
, "1"
, "12"
, "123"
, "1234"
, "12345"
, "123456"
, "1234567"
, "12345678"
, "123456789"
, "1234567890"
, ".12"
, "1.12"
, "12.12"
, "123.12"
, "1234.12"
, "12345.12"
, "123456.12"
, "1234567.12"
, "12345678.12"
, "123456789.12"
, "1234567890.12"
, "1234567890.123"
, "1234567890.125"
].forEach(function (item) {
console.log(format(item));
});
得到了这些结果：
0.00
1.00
12.00
123.00
1,234.00
12,345.00
123,456.00
1,234,567.00
12,345,678.00
123,456,789.00
1,234,567,890.00
0.12
1.12
12.12
123.12
1,234.12
12,345.12
123,456.12
1,234,567.12
12,345,678.12
123,456,789.12
1,234,567,890.12
1,234,567,890.12
1,234,567,890.13
只是为了好玩。
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
下面是Patrick Desjardins（别名Daok）代码，添加了一些注释和一些小改动：
/*
decimal_sep: character used as decimal separator, it defaults to '.' when omitted
thousands_sep: char used as thousands separator, it defaults to ',' when omitted
*/
Number.prototype.toMoney = function(decimals, decimal_sep, thousands_sep)
{
var n = this,
c = isNaN(decimals) ? 2 : Math.abs(decimals), // If decimal is zero we must take it. It means the user does not want to show any decimal
d = decimal_sep || '.', // If no decimal separator is passed, we use the dot as default decimal separator (we MUST use a decimal separator)
/*
According to [https://stackoverflow.com/questions/411352/how-best-to-determine-if-an-argument-is-not-sent-to-the-javascript-function]
the fastest way to check for not defined parameter is to use typeof value === 'undefined'
rather than doing value === undefined.
*/
t = (typeof thousands_sep === 'undefined') ? ',' : thousands_sep, // If you don't want to use a thousands separator you can pass empty string as thousands_sep value
sign = (n < 0) ? '-' : '',
// Extracting the absolute value of the integer part of the number and converting to string
i = parseInt(n = Math.abs(n).toFixed(c)) + '',
j = ((j = i.length) > 3) ? j % 3 : 0;
return sign + (j ? i.substr(0, j) + t : '') + i.substr(j).replace(/(\d{3})(?=\d)/g, "$1" + t) + (c ? d + Math.abs(n - i).toFixed(c).slice(2) : '');
}
这里有一些测试：
// Some tests (do not forget parenthesis when using negative numbers and number with no decimals)
alert(123456789.67392.toMoney() + '\n' + 123456789.67392.toMoney(3) + '\n' + 123456789.67392.toMoney(0) + '\n' + (123456).toMoney() + '\n' + (123456).toMoney(0) + '\n' + 89.67392.toMoney() + '\n' + (89).toMoney());
// Some tests (do not forget parenthesis when using negative numbers and number with no decimals)
alert((-123456789.67392).toMoney() + '\n' + (-123456789.67392).toMoney(-3));
次要变化包括：
移动了一点Math.abs（小数），只有当不是NaN时才能执行。decimal_sep不能再是空字符串（必须使用某种十进制分隔符）我们使用typeof thousand_sep===“undefined”，如How best to determine if a argument is not send to JavaScript function中所建议的不需要（+n||0），因为这是Number对象
JSFiddle公司
PHP函数“number_format”有一个JavaScript端口。
我发现它非常有用，因为它易于使用，并且对PHP开发人员来说是可识别的。
function number_format (number, decimals, dec_point, thousands_sep) {
var n = number, prec = decimals;
var toFixedFix = function (n,prec) {
var k = Math.pow(10,prec);
return (Math.round(n*k)/k).toString();
};
n = !isFinite(+n) ? 0 : +n;
prec = !isFinite(+prec) ? 0 : Math.abs(prec);
var sep = (typeof thousands_sep === 'undefined') ? ',' : thousands_sep;
var dec = (typeof dec_point === 'undefined') ? '.' : dec_point;
var s = (prec > 0) ? toFixedFix(n, prec) : toFixedFix(Math.round(n), prec);
// Fix for Internet Explorer parseFloat(0.55).toFixed(0) = 0;
var abs = toFixedFix(Math.abs(n), prec);
var _, i;
if (abs >= 1000) {
_ = abs.split(/\D/);
i = _[0].length % 3 || 3;
_[0] = s.slice(0,i + (n < 0)) +
_[0].slice(i).replace(/(\d{3})/g, sep+'$1');
s = _.join(dec);
} else {
s = s.replace('.', dec);
}
var decPos = s.indexOf(dec);
if (prec >= 1 && decPos !== -1 && (s.length-decPos-1) < prec) {
s += new Array(prec-(s.length-decPos-1)).join(0)+'0';
}
else if (prec >= 1 && decPos === -1) {
s += dec+new Array(prec).join(0)+'0';
}
return s;
}
（原文注释栏，包括以下示例和到期信用）
// Formats a number with grouped thousands
//
// version: 906.1806
// discuss at: http://phpjs.org/functions/number_format
// + original by: Jonas Raoni Soares Silva (http://www.jsfromhell.com)
// + improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
// + bugfix by: Michael White (http://getsprink.com)
// + bugfix by: Benjamin Lupton
// + bugfix by: Allan Jensen (http://www.winternet.no)
// + revised by: Jonas Raoni Soares Silva (http://www.jsfromhell.com)
// + bugfix by: Howard Yeend
// + revised by: Luke Smith (http://lucassmith.name)
// + bugfix by: Diogo Resende
// + bugfix by: Rival
// + input by: Kheang Hok Chin (http://www.distantia.ca/)
// + improved by: davook
// + improved by: Brett Zamir (http://brett-zamir.me)
// + input by: Jay Klehr
// + improved by: Brett Zamir (http://brett-zamir.me)
// + input by: Amir Habibi (http://www.residence-mixte.com/)
// + bugfix by: Brett Zamir (http://brett-zamir.me)
// * example 1: number_format(1234.56);
// * returns 1: '1,235'
// * example 2: number_format(1234.56, 2, ',', ' ');
// * returns 2: '1 234,56'
// * example 3: number_format(1234.5678, 2, '.', '');
// * returns 3: '1234.57'
// * example 4: number_format(67, 2, ',', '.');
// * returns 4: '67,00'
// * example 5: number_format(1000);
// * returns 5: '1,000'
// * example 6: number_format(67.311, 2);
// * returns 6: '67.31'
// * example 7: number_format(1000.55, 1);
// * returns 7: '1,000.6'
// * example 8: number_format(67000, 5, ',', '.');
// * returns 8: '67.000,00000'
// * example 9: number_format(0.9, 0);
// * returns 9: '1'
// * example 10: number_format('1.20', 2);
// * returns 10: '1.20'
// * example 11: number_format('1.20', 4);
// * returns 11: '1.2000'
// * example 12: number_format('1.2000', 3);
// * returns 12: '1.200'
数字（值）.to固定（2）.replace（/（\d）（？=（\d｛3｝）+（？！\d））/g，“$1，”）
