Javascript 货币格式化函数

平时我们有可能遇到需要把网站中的数字（通常是价格）用一种统一的方式显示出来，比如每隔3个字符加一个空格。如果数值比较大的话这种方法很有利于用户阅读。

用XSLT的朋友可能知道在XSL中可以用如下代码实现

<xsl:decimal-format name="currency" decimal-separator="." grouping-separator=" "/>

今天研究了一下，写了一个对应的javascript代码.

有趣的部分是方法二是用正则表达式实现的，非常明了！

function currencyFormatter(oNum,decimalSeparator,groupingNumber,groupingSeparator){

//check type

if(isNaN(parseFloat(oNum))){

alert(oNum + 'is not a number!');

return "";

}

//get sign and make oNum to abstract

var sign = (oNum == (oNum = Math.abs(oNum)));

//get fraction

var nDecimalString = oNum + '';

var nIndex = nDecimalString.indexOf('.');

var sFraction = '';

if(nIndex != -1){

sFraction = nDecimalString.substr(nIndex);

}

//get integer

var nInteger = parseInt(Math.floor(oNum));

var nInegerString = nInteger + '';

//insert separator

var aResult = [];

//method 1

/*

var length = nInegerString.length;

for (var i=length; i > 0 ; i-=groupingNumber) {

var nextI = i - groupingNumber;

if(nextI <= 0){

break;

}

aResult.unshift(nInegerString.substring(nextI,i));

aResult.unshift(groupingSeparator);

};

if(nextI <= 0){

aResult.unshift(nInegerString.substring(nextI,i));

}

*/

//method 2

aResult = nInegerString.split("");

aResult = aResult.reverse();

var exp= new RegExp("(//d{"+groupingNumber+"})",'g');

aResult = aResult.join('').replace(exp,'$1'+groupingSeparator)

aResult = aResult.split('');

aResult = aResult.reverse();

//put things together

var sReturn = ((sign)?'':'-') + aResult.join('') + sFraction;

if(decimalSeparator){

sReturn = sReturn.replace(".",decimalSeparator);

}

return sReturn;

}

例子：

currencyFormatter(-1234567890.323234,',',3,',')

结果 -1,234,567,890,323234