JS格式化数字的千分位

<script src="jquery-1.6.js" language="javascript" type="text/javascript"></script>
<script language="javascript" type="text/javascript">
$(function(){
var temp = MilliFormat(100000.01);
alert(temp);
});

function MilliFormat(fSum){
var re = new RegExp("^(-?\\d+)(\\.\\d+)?{1}quot;); //判断是否是浮点数
var strSum;
var behind = "";
if (re.test(fSum))
{
strSum = new String(fSum);
}
else
{
return "";
}

if(strSum.indexOf(".") > -1) {
behind = strSum.split(".")[1];
strSum = strSum.split(".")[0];
}
var len;
var result = "";
var temp = "";
len = strSum.length;
while(len > 3){
temp = ","+strSum.substring(len - 3,len);
strSum = strSum.substring(0,len - 3);
result = temp + result;
len = strSum.length;
}
if(len > 0)
{
result = strSum + result;
}
if(behind!="")
result += "." + behind;

return result;
}

</script>