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
好的，根据你说的，我用这个：
var DecimalSeparator = Number("1.2").toLocaleString().substr(1,1);
var AmountWithCommas = Amount.toLocaleString();
var arParts = String(AmountWithCommas).split(DecimalSeparator);
var intPart = arParts[0];
var decPart = (arParts.length > 1 ? arParts[1] : '');
decPart = (decPart + '00').substr(0,2);
return '£ ' + intPart + DecimalSeparator + decPart;
我对改进建议持开放态度（我不希望仅仅为了做到这一点而加入YUI：-）
我已经知道我应该检测“.”而不是仅仅将其用作小数分隔符。。。
其他回答
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
请在下面的代码中找到我为支持国际化而开发的内容。
它将给定的数值格式化为特定于语言的格式。在给定的示例中，我使用了“en”，同时测试了“es”、“fr”和其他格式不同的国家。它不仅可以阻止用户键入字符，还可以格式化制表符上的值。
我已经为数字和十进制格式创建了组件。除此之外，我还创建了parseNumber（value，locale）和parseDecimal（value，locale）函数，这些函数将解析格式化数据以用于任何其他业务目的。所述函数将接受格式化数据并返回非格式化值。我在下面的共享代码中使用了jQuery验证器插件。
HTML格式：
<tr>
<td>
<label class="control-label">
Number Field:
</label>
<div class="inner-addon right-addon">
<input type="text" id="numberField"
name="numberField"
class="form-control"
autocomplete="off"
maxlength="17"
data-rule-required="true"
data-msg-required="Cannot be blank."
data-msg-maxlength="Exceeding the maximum limit of 13 digits. Example: 1234567890123"
data-rule-numberExceedsMaxLimit="en"
data-msg-numberExceedsMaxLimit="Exceeding the maximum limit of 13 digits. Example: 1234567890123"
onkeydown="return isNumber(event, 'en')"
onkeyup="return updateField(this)"
onblur="numberFormatter(this,
'en',
'Invalid character(s) found. Please enter valid characters.')">
</div>
</td>
</tr>
<tr>
<td>
<label class="control-label">
Decimal Field:
</label>
<div class="inner-addon right-addon">
<input type="text" id="decimalField"
name="decimalField"
class="form-control"
autocomplete="off"
maxlength="20"
data-rule-required="true"
data-msg-required="Cannot be blank."
data-msg-maxlength="Exceeding the maximum limit of 16 digits. Example: 1234567890123.00"
data-rule-decimalExceedsMaxLimit="en"
data-msg-decimalExceedsMaxLimit="Exceeding the maximum limit of 16 digits. Example: 1234567890123.00"
onkeydown="return isDecimal(event, 'en')"
onkeyup="return updateField(this)"
onblur="decimalFormatter(this,
'en',
'Invalid character(s) found. Please enter valid characters.')">
</div>
</td>
</tr>
JavaScript：
/*
* @author: dinesh.lomte
*/
/* Holds the maximum limit of digits to be entered in number field. */
var numericMaxLimit = 13;
/* Holds the maximum limit of digits to be entered in decimal field. */
var decimalMaxLimit = 16;
/**
*
* @param {type} value
* @param {type} locale
* @returns {Boolean}
*/
parseDecimal = function(value, locale) {
value = value.trim();
if (isNull(value)) {
return 0.00;
}
if (isNull(locale)) {
return value;
}
if (getNumberFormat(locale)[0] === '.') {
value = value.replace(/\./g, '');
} else {
value = value.replace(
new RegExp(getNumberFormat(locale)[0], 'g'), '');
}
if (getNumberFormat(locale)[1] === ',') {
value = value.replace(
new RegExp(getNumberFormat(locale)[1], 'g'), '.');
}
return value;
};
/**
*
* @param {type} element
* @param {type} locale
* @param {type} nanMessage
* @returns {Boolean}
*/
decimalFormatter = function (element, locale, nanMessage) {
showErrorMessage(element.id, false, null);
if (isNull(element.id) || isNull(element.value) || isNull(locale)) {
return true;
}
var value = element.value.trim();
value = value.replace(/\s/g, '');
value = parseDecimal(value, locale);
var numberFormatObj = new Intl.NumberFormat(locale,
{ minimumFractionDigits: 2,
maximumFractionDigits: 2
}
);
if (numberFormatObj.format(value) === 'NaN') {
showErrorMessage(element.id, true, nanMessage);
setFocus(element.id);
return false;
}
element.value = numberFormatObj.format(value);
return true;
};
/**
*
* @param {type} element
* @param {type} locale
* @param {type} nanMessage
* @returns {Boolean}
*/
numberFormatter = function (element, locale, nanMessage) {
showErrorMessage(element.id, false, null);
if (isNull(element.id) || isNull(element.value) || isNull(locale)) {
return true;
}
var value = element.value.trim();
var format = getNumberFormat(locale);
if (hasDecimal(value, format[1])) {
showErrorMessage(element.id, true, nanMessage);
setFocus(element.id);
return false;
}
value = value.replace(/\s/g, '');
value = parseNumber(value, locale);
var numberFormatObj = new Intl.NumberFormat(locale,
{ minimumFractionDigits: 0,
maximumFractionDigits: 0
}
);
if (numberFormatObj.format(value) === 'NaN') {
showErrorMessage(element.id, true, nanMessage);
setFocus(element.id);
return false;
}
element.value =
numberFormatObj.format(value);
return true;
};
/**
*
* @param {type} id
* @param {type} flag
* @param {type} message
* @returns {undefined}
*/
showErrorMessage = function(id, flag, message) {
if (flag) {
// only add if not added
if ($('#'+id).parent().next('.app-error-message').length === 0) {
var errorTag = '<div class=\'app-error-message\'>' + message + '</div>';
$('#'+id).parent().after(errorTag);
}
} else {
// remove it
$('#'+id).parent().next(".app-error-message").remove();
}
};
/**
*
* @param {type} id
* @returns
*/
setFocus = function(id) {
id = id.trim();
if (isNull(id)) {
return;
}
setTimeout(function() {
document.getElementById(id).focus();
}, 10);
};
/**
*
* @param {type} value
* @param {type} locale
* @returns {Array}
*/
parseNumber = function(value, locale) {
value = value.trim();
if (isNull(value)) {
return 0;
}
if (isNull(locale)) {
return value;
}
if (getNumberFormat(locale)[0] === '.') {
return value.replace(/\./g, '');
}
return value.replace(
new RegExp(getNumberFormat(locale)[0], 'g'), '');
};
/**
*
* @param {type} locale
* @returns {Array}
*/
getNumberFormat = function(locale) {
var format = [];
var numberFormatObj = new Intl.NumberFormat(locale,
{ minimumFractionDigits: 2,
maximumFractionDigits: 2
}
);
var value = numberFormatObj.format('132617.07');
format[0] = value.charAt(3);
format[1] = value.charAt(7);
return format;
};
/**
*
* @param {type} value
* @param {type} fractionFormat
* @returns {Boolean}
*/
hasDecimal = function(value, fractionFormat) {
value = value.trim();
if (isNull(value) || isNull(fractionFormat)) {
return false;
}
if (value.indexOf(fractionFormat) >= 1) {
return true;
}
};
/**
*
* @param {type} event
* @param {type} locale
* @returns {Boolean}
*/
isNumber = function(event, locale) {
var keyCode = event.which ? event.which : event.keyCode;
// Validating if user has pressed shift character
if (keyCode === 16) {
return false;
}
if (isNumberKey(keyCode)) {
return true;
}
var numberFormatter = [32, 110, 188, 190];
if (keyCode === 32
&& isNull(getNumberFormat(locale)[0]) === isNull(getFormat(keyCode))) {
return true;
}
if (numberFormatter.indexOf(keyCode) >= 0
&& getNumberFormat(locale)[0] === getFormat(keyCode)) {
return true;
}
return false;
};
/**
*
* @param {type} event
* @param {type} locale
* @returns {Boolean}
*/
isDecimal = function(event, locale) {
var keyCode = event.which ? event.which : event.keyCode;
// Validating if user has pressed shift character
if (keyCode === 16) {
return false;
}
if (isNumberKey(keyCode)) {
return true;
}
var numberFormatter = [32, 110, 188, 190];
if (keyCode === 32
&& isNull(getNumberFormat(locale)[0]) === isNull(getFormat(keyCode))) {
return true;
}
if (numberFormatter.indexOf(keyCode) >= 0
&& (getNumberFormat(locale)[0] === getFormat(keyCode)
|| getNumberFormat(locale)[1] === getFormat(keyCode))) {
return true;
}
return false;
};
/**
*
* @param {type} keyCode
* @returns {Boolean}
*/
isNumberKey = function(keyCode) {
if ((keyCode >= 48 && keyCode <= 57) ||
(keyCode >= 96 && keyCode <= 105)) {
return true;
}
var keys = [8, 9, 13, 35, 36, 37, 39, 45, 46, 109, 144, 173, 189];
if (keys.indexOf(keyCode) !== -1) {
return true;
}
return false;
};
/**
*
* @param {type} keyCode
* @returns {JSON@call;parse.numberFormatter.value|String}
*/
getFormat = function(keyCode) {
var jsonString = '{"numberFormatter" : [{"key":"32", "value":" ", "description":"space"}, {"key":"188", "value":",", "description":"comma"}, {"key":"190", "value":".", "description":"dot"}, {"key":"110", "value":".", "description":"dot"}]}';
var jsonObject = JSON.parse(jsonString);
for (var key in jsonObject.numberFormatter) {
if (jsonObject.numberFormatter.hasOwnProperty(key)
&& keyCode === parseInt(jsonObject.numberFormatter[key].key)) {
return jsonObject.numberFormatter[key].value;
}
}
return '';
};
/**
*
* @type String
*/
var jsonString = '{"shiftCharacterNumberMap" : [{"char":")", "number":"0"}, {"char":"!", "number":"1"}, {"char":"@", "number":"2"}, {"char":"#", "number":"3"}, {"char":"$", "number":"4"}, {"char":"%", "number":"5"}, {"char":"^", "number":"6"}, {"char":"&", "number":"7"}, {"char":"*", "number":"8"}, {"char":"(", "number":"9"}]}';
/**
*
* @param {type} value
* @returns {JSON@call;parse.shiftCharacterNumberMap.number|String}
*/
getShiftCharSpecificNumber = function(value) {
var jsonObject = JSON.parse(jsonString);
for (var key in jsonObject.shiftCharacterNumberMap) {
if (jsonObject.shiftCharacterNumberMap.hasOwnProperty(key)
&& value === jsonObject.shiftCharacterNumberMap[key].char) {
return jsonObject.shiftCharacterNumberMap[key].number;
}
}
return '';
};
/**
*
* @param {type} value
* @returns {Boolean}
*/
isShiftSpecificChar = function(value) {
var jsonObject = JSON.parse(jsonString);
for (var key in jsonObject.shiftCharacterNumberMap) {
if (jsonObject.shiftCharacterNumberMap.hasOwnProperty(key)
&& value === jsonObject.shiftCharacterNumberMap[key].char) {
return true;
}
}
return false;
};
/**
*
* @param {type} element
* @returns {undefined}
*/
updateField = function(element) {
var value = element.value;
for (var index = 0; index < value.length; index++) {
if (!isShiftSpecificChar(value.charAt(index))) {
continue;
}
element.value = value.replace(
value.charAt(index),
getShiftCharSpecificNumber(value.charAt(index)));
}
};
/**
*
* @param {type} value
* @param {type} element
* @param {type} params
*/
jQuery.validator.addMethod('numberExceedsMaxLimit', function(value, element, params) {
value = parseInt(parseNumber(value, params));
if (value.toString().length > numericMaxLimit) {
showErrorMessage(element.id, false, null);
setFocus(element.id);
return false;
}
return true;
}, 'Exceeding the maximum limit of 13 digits. Example: 1234567890123.');
/**
*
* @param {type} value
* @param {type} element
* @param {type} params
*/
jQuery.validator.addMethod('decimalExceedsMaxLimit', function(value, element, params) {
value = parseFloat(parseDecimal(value, params)).toFixed(2);
if (value.toString().substring(
0, value.toString().lastIndexOf('.')).length > numericMaxLimit
|| value.toString().length > decimalMaxLimit) {
showErrorMessage(element.id, false, null);
setFocus(element.id);
return false;
}
return true;
}, 'Exceeding the maximum limit of 16 digits. Example: 1234567890123.00.');
/**
* @param {type} id
* @param {type} locale
* @returns {boolean}
*/
isNumberExceedMaxLimit = function(id, locale) {
var value = parseInt(parseNumber(
document.getElementById(id).value, locale));
if (value.toString().length > numericMaxLimit) {
setFocus(id);
return true;
}
return false;
};
/**
* @param {type} id
* @param {type} locale
* @returns {boolean}
*/
isDecimalExceedsMaxLimit = function(id, locale) {
var value = parseFloat(parseDecimal(
document.getElementById(id).value, locale)).toFixed(2);
if (value.toString().substring(
0, value.toString().lastIndexOf('.')).length > numericMaxLimit
|| value.toString().length > decimalMaxLimit) {
setFocus(id);
return true;
}
return false;
};
这里是XMLilley提供的代码的mootools1.2实现。。。
Number.implement('format', function(decPlaces, thouSeparator, decSeparator){
decPlaces = isNaN(decPlaces = Math.abs(decPlaces)) ? 2 : decPlaces;
decSeparator = decSeparator === undefined ? '.' : decSeparator;
thouSeparator = thouSeparator === undefined ? ',' : thouSeparator;
var num = this,
sign = num < 0 ? '-' : '',
i = parseInt(num = Math.abs(+num || 0).toFixed(decPlaces)) + '',
j = (j = i.length) > 3 ? j % 3 : 0;
return sign + (j ? i.substr(0, j) + thouSeparator : '') + i.substr(j).replace(/(\d{3})(?=\d)/g, '$1' + thouSeparator) + (decPlaces ? decSeparator + Math.abs(num - i).toFixed(decPlaces).slice(2) : '');
});
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！：）
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];
}
