JS将number数值转化成为货币格式

JS将number数值转化成为货币格式：

这里第一个方法是用JavaScript将数字number转换为货币字符串的格式(参数：保留小数位数，货币符号，整数部分千位分隔符，小数分隔符)

这里第二个方法是用简单的正则表达式将货币字符换转换为纯净的数字字符串，之后便可以将字符串转换为数字number

JavaScript Money Format（用prototype对Number进行扩展）

// Extend the default Number object with a formatMoney() method:
    // usage: someVar.formatMoney(decimalPlaces, symbol, thousandsSeparator, decimalSeparator)
    // defaults: (2, "$", ",", ".")
    Number.prototype.formatMoney = function (places, symbol, thousand, decimal) {
        places = !isNaN(places = Math.abs(places)) ? places : 2;
        symbol = symbol !== undefined ? symbol : "$";
        thousand = thousand || ",";
        decimal = decimal || ".";
        var number = this,
            negative = number < 0 ? "-" : "",
            i = parseInt(number = Math.abs(+number || 0).toFixed(places), 10) + "",
            j = (j = i.length) > 3 ? j % 3 : 0;
        return symbol + negative + (j ? i.substr(0, j) + thousand : "") + i.substr(j).replace(/(\d{3})(?=\d)/g, "$1" + thousand) + (places ? decimal + Math.abs(number - i).toFixed(places).slice(2) : "");
    };

如下便是一些转换实例：

    // Default usage and custom precision/symbol :
    var revenue = 12345678;
    alert(revenue.formatMoney()); // $12,345,678.00
    alert(revenue.formatMoney(0, "HK$ ")); // HK$ 12,345,678

    // European formatting:
    var price = 4999.99;
    alert(price.formatMoney(2, "€", ".", ",")); // €4.999,99

    // It works for negative values, too:
    alert((-500000).formatMoney(0, "£ ")); // £ -500,000

Currency to number – removing money formatting （用正则表达式进行过滤）

    var price = (12345.99).formatMoney(); // "$12,345.99"

    // Remove non-numeric chars (except decimal point/minus sign):
    priceVal = parseFloat(price.replace(/[^0-9-.]/g, '')); // 12345.99

这个方法仅仅应用于小数分隔符为"."的模式，如果小数分隔符是"," 那么正则表达式为/[^0-9-,]/g

不用prototype对Number进行拓展的版本：

    // To set it up as a global function:
    function formatMoney(number, places, symbol, thousand, decimal) {
        number = number || 0;
        places = !isNaN(places = Math.abs(places)) ? places : 2;
        symbol = symbol !== undefined ? symbol : "$";
        thousand = thousand || ",";
        decimal = decimal || ".";
        var negative = number < 0 ? "-" : "",
            i = parseInt(number = Math.abs(+number || 0).toFixed(places), 10) + "",
            j = (j = i.length) > 3 ? j % 3 : 0;
        return symbol + negative + (j ? i.substr(0, j) + thousand : "") + i.substr(j).replace(/(\d{3})(?=\d)/g, "$1" + thousand) + (places ? decimal + Math.abs(number - i).toFixed(places).slice(2) : "");
    }

    // To create it as a library method:
    myLibrary.formatMoney = function (number, places, symbol, thousand, decimal) {
        /* as above */
    }

    // Example usage:
    formatMoney(54321); // $54,321
    myLibrary.formatMoney(12345, 0, "£ "); // £ 12,345