js 数字，金额 用逗号 隔开。数字格式化

<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">