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, ""));??
}

<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">