例如：
12345格式化为12,345.00
12345.6格式化为12,345.60
12345.67格式化为 12,345.67
只留两位小数。
回来后写了个格式化函数。可以控制小数位数，自动四舍五入。代码如下：
function fmoney(s, n) {n = n > 0 && n <= 20 ? n : 2;s = parseFloat((s + "").replace(/[^\d\.-]/g, "")).toFixed(n) + "";var l = s.split(".")[0].split("").reverse(), r = s.split(".")[1];t = "";for (i = 0; i < l.length; i++) {t += l[i] + ((i + 1) % 3 == 0 && (i + 1) != l.length ? "," : "");}return t.split("").reverse().join("") + "." + r;}
调用：fmoney("12345.675910", 3)，返回12,345.676
还原函数：
function rmoney(s) {return parseFloat(s.replace(/[^\d\.-]/g, ""));}
示例（可保存一下代码为html文件，运行查看效果）：
<SCRIPT>function fmoney(s, n) {n = n > 0 && n <= 20 ? n : 2;s = parseFloat((s + "").replace(/[^\d\.-]/g, "")).toFixed(n) + "";var l = s.split(".")[0].split("").reverse(), r = s.split(".")[1];t = "";for (i = 0; i < l.length; i++) {t += l[i] + ((i + 1) % 3 == 0 && (i + 1) != l.length ? "," : "");}return t.split("").reverse().join("") + "." + r;}function rmoney(s) {return parseFloat(s.replace(/[^\d\.-]/g, ""));}function g(id) {return document.getElementById(id);}window.onload = function() {var num, txt = g("txt"), txt2 = g("txt2"), btn = g("btn"), btn2 = g("btn2"), span = g("span");btn.onclick = function() {num = parseInt(g("num").value);txt.value = fmoney(txt.value, num);txt2.value = fmoney(txt2.value, num);};btn2.onclick = function() {num = parseInt(g("num").value);span.innerHTML = "="+ fmoney(rmoney(txt.value) + rmoney(txt2.value), num);};};</SCRIPT> 小数点位数： <select id="num"> <option value="2">2</option> <option value="3">3</option> <option value="4">4</option> <option value="5">5</option> </select> <input type="text" id="txt" value="12345.675910"> + <input type="text" id="txt2" value="1223"> <span id="span"></span> <br> <input type="button" id="btn" value="格式化"> <input type="button" id="btn2" value="相加">
附：
/** formatMoney(s,type)* 功能：金额按千位逗号分割* 参数：s，需要格式化的金额数值.* 参数：type,判断格式化后的金额是否需要小数位.* 返回：返回格式化后的数值字符串.*/function formatMoney(s, type) {if (/[^0-9\.]/.test(s))return "0";if (s == null || s == "")return "0";s = s.toString().replace(/^(\d*)$/, "$1.");s = (s + "00").replace(/(\d*\.\d\d)\d*/, "$1");s = s.replace(".", ",");var re = /(\d)(\d{3},)/;while (re.test(s))s = s.replace(re, "$1,$2");s = s.replace(/,(\d\d)$/, ".$1");if (type == 0) {// 不带小数位(默认是有小数位)var a = s.split(".");if (a[1] == "00") {s = a[0];}}return s;}/** 通用DateAdd(interval,number,date) 功能:实现javascript的日期相加功能.* 参数:interval,字符串表达式，表示要添加的时间间隔. 参数:number,数值表达式，表示要添加的时间间隔的个数. 参数:date,时间对象.* 返回:新的时间对象. var now = new Date(); var newDate = DateAdd("day",5,now);* author:devinhua(从○开始) update:-5-5 20:35*/function DateAdd(interval, number, date) {if (date == null)return "";switch (interval) {case "day":date = new Date(date);date = date.valueOf();date += number * 24 * 60 * 60 * 1000;date = new Date(date);return date;break;default:return "";break;}}
