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

http://code.google.com/p/javascript-number-formatter/:

短、快、灵活但独立。只有75行,包括MIT许可证信息、空白行和注释。接受标准数字格式,如#、##0.00或带否定的-000.####。接受任何国家/地区格式,如###0,00,#,###.##,#‘###.##或任何类型的非编号符号。接受任意数字分组。#、##、#0.000或#、####0.##均有效。接受任何冗余/防傻瓜格式。##、###、##。#或0#、#00####0#都正常。自动数字舍入。简单的界面,只需提供如下掩码和值:格式(“0.0000”,3.141592)

UPDATE这是我自己开发的应用程序,用于最常见的任务:

var NumUtil = {};

/**
  Petty print 'num' wth exactly 'signif' digits.
  pp(123.45, 2) == "120"
  pp(0.012343, 3) == "0.0123"
  pp(1.2, 3) == "1.20"
*/
NumUtil.pp = function(num, signif) {
    if (typeof(num) !== "number")
        throw 'NumUtil.pp: num is not a number!';
    if (isNaN(num))
        throw 'NumUtil.pp: num is NaN!';
    if (num < 1e-15 || num > 1e15)
        return num;
    var r = Math.log(num)/Math.LN10;
    var dot = Math.floor(r) - (signif-1);
    r = r - Math.floor(r) + (signif-1);
    r = Math.round(Math.exp(r * Math.LN10)).toString();
    if (dot >= 0) {
        for (; dot > 0; dot -= 1)
            r += "0";
        return r;
    } else if (-dot >= r.length) {
        var p = "0.";
        for (; -dot > r.length; dot += 1) {
            p += "0";
        }
        return p+r;
    } else {
        return r.substring(0, r.length + dot) + "." + r.substring(r.length + dot);
    }
}

/** Append leading zeros up to 2 digits. */
NumUtil.align2 = function(v) {
    if (v < 10)
        return "0"+v;
    return ""+v;
}
/** Append leading zeros up to 3 digits. */
NumUtil.align3 = function(v) {
    if (v < 10)
        return "00"+v;
    else if (v < 100)
        return "0"+v;
    return ""+v;
}

NumUtil.integer = {};

/** Round to integer and group by 3 digits. */
NumUtil.integer.pp = function(num) {
    if (typeof(num) !== "number") {
        console.log("%s", new Error().stack);
        throw 'NumUtil.integer.pp: num is not a number!';
    }
    if (isNaN(num))
        throw 'NumUtil.integer.pp: num is NaN!';
    if (num > 1e15)
        return num;
    if (num < 0)
        throw 'Negative num!';
    num = Math.round(num);
    var group = num % 1000;
    var integ = Math.floor(num / 1000);
    if (integ === 0) {
        return group;
    }
    num = NumUtil.align3(group);
    while (true) {
        group = integ % 1000;
        integ = Math.floor(integ / 1000);
        if (integ === 0)
            return group + " " + num;
        num = NumUtil.align3(group) + " " + num;
    }
    return num;
}

NumUtil.currency = {};

/** Round to coins and group by 3 digits. */
NumUtil.currency.pp = function(amount) {
    if (typeof(amount) !== "number")
        throw 'NumUtil.currency.pp: amount is not a number!';
    if (isNaN(amount))
        throw 'NumUtil.currency.pp: amount is NaN!';
    if (amount > 1e15)
        return amount;
    if (amount < 0)
        throw 'Negative amount!';
    if (amount < 1e-2)
        return 0;
    var v = Math.round(amount*100);
    var integ = Math.floor(v / 100);
    var frac = NumUtil.align2(v % 100);
    var group = integ % 1000;
    integ = Math.floor(integ / 1000);
    if (integ === 0) {
        return group + "." + frac;
    }
    amount = NumUtil.align3(group);
    while (true) {
        group = integ % 1000;
        integ = Math.floor(integ / 1000);
        if (integ === 0)
            return group + " " + amount + "." + frac;
        amount = NumUtil.align3(group) + " " + amount;
    }
    return amount;
}

其他回答

主要部分是插入千个分隔符,可以这样做:

<script type="text/javascript">
  function ins1000Sep(val) {
    val = val.split(".");
    val[0] = val[0].split("").reverse().join("");
    val[0] = val[0].replace(/(\d{3})/g, "$1,");
    val[0] = val[0].split("").reverse().join("");
    val[0] = val[0].indexOf(",") == 0 ? val[0].substring(1) : val[0];
    return val.join(".");
  }

  function rem1000Sep(val) {
    return val.replace(/,/g, "");
  }

  function formatNum(val) {
    val = Math.round(val*100)/100;
    val = ("" + val).indexOf(".") > -1 ? val + "00" : val + ".00";
    var dec = val.indexOf(".");
    return dec == val.length-3 || dec == 0 ? val : val.substring(0, dec+3);
  }
</script>

<button onclick="alert(ins1000Sep(formatNum(12313231)));">

YUI代码库使用以下格式:

format: function(nData, oConfig) {
    oConfig = oConfig || {};

    if(!YAHOO.lang.isNumber(nData)) {
        nData *= 1;
    }

    if(YAHOO.lang.isNumber(nData)) {
        var sOutput = nData + "";
        var sDecimalSeparator = (oConfig.decimalSeparator) ? oConfig.decimalSeparator : ".";
        var nDotIndex;

        // Manage decimals
        if(YAHOO.lang.isNumber(oConfig.decimalPlaces)) {
            // Round to the correct decimal place
            var nDecimalPlaces = oConfig.decimalPlaces;
            var nDecimal = Math.pow(10, nDecimalPlaces);
            sOutput = Math.round(nData*nDecimal)/nDecimal + "";
            nDotIndex = sOutput.lastIndexOf(".");

            if(nDecimalPlaces > 0) {
                // Add the decimal separator
                if(nDotIndex < 0) {
                    sOutput += sDecimalSeparator;
                    nDotIndex = sOutput.length-1;
                }
                // Replace the "."
                else if(sDecimalSeparator !== "."){
                    sOutput = sOutput.replace(".",sDecimalSeparator);
                }
                // Add missing zeros
                while((sOutput.length - 1 - nDotIndex) < nDecimalPlaces) {
                    sOutput += "0";
                }
            }
        }

        // Add the thousands separator
        if(oConfig.thousandsSeparator) {
            var sThousandsSeparator = oConfig.thousandsSeparator;
            nDotIndex = sOutput.lastIndexOf(sDecimalSeparator);
            nDotIndex = (nDotIndex > -1) ? nDotIndex : sOutput.length;
            var sNewOutput = sOutput.substring(nDotIndex);
            var nCount = -1;
            for (var i=nDotIndex; i>0; i--) {
                nCount++;
                if ((nCount%3 === 0) && (i !== nDotIndex)) {
                    sNewOutput = sThousandsSeparator + sNewOutput;
                }
                sNewOutput = sOutput.charAt(i-1) + sNewOutput;
            }
            sOutput = sNewOutput;
        }

        // Prepend prefix
        sOutput = (oConfig.prefix) ? oConfig.prefix + sOutput : sOutput;

        // Append suffix
        sOutput = (oConfig.suffix) ? sOutput + oConfig.suffix : sOutput;

        return sOutput;
    }
    // Still not a number. Just return it unaltered
    else {
        return nData;
    }
}

它需要编辑,因为YUI库是可配置的,比如用“.”替换oConfig.decimalSeparator。

使用regexp的更快方法:

Number.prototype.toMonetaryString = function() {
  var n = this.toFixed(2), m;
  //var = this.toFixed(2).replace(/\./, ','); For comma separator
  // with a space for thousands separator
  while ((m = n.replace(/(\d)(\d\d\d)\b/g, '$1 $2')) != n)
      n = m;
  return m;
}

String.prototype.fromMonetaryToNumber = function(s) {
  return this.replace(/[^\d-]+/g, '')/100;
}

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!:)

看看JavaScriptNumber对象,看看它是否可以帮助您。

toLocaleString()将使用位置特定的千位分隔符格式化数字。toFixed()将数字舍入到特定的小数位数。

要同时使用这些值,必须将其类型改回数字,因为它们都输出字符串。

例子:

Number((someNumber).toFixed(1)).toLocaleString()

EDIT

您可以直接使用toLocaleString,而不必重新转换为数字:

someNumber.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});

多个数字

如果需要经常以类似的方式格式化数字,可以创建一个特定的对象以供重用。德语(瑞士):

const money = new Intl.NumberFormat('de-CH',
  { style:'currency', currency: 'CHF' });
const percent = new Intl.NumberFormat('de-CH',
  { style:'percent', maximumFractionDigits: 1, signDisplay: "always"});

其可以用作:

money.format(1234.50); // output CHF 1'234.50
percent.format(0.083);  // output +8.3%

非常漂亮。