数字千位加逗号js

<script  type= "text/javascript">
    var   num_s = "1232134456.546 ";alert(parseFloat(num_s).toLocaleString());
</script>
<script type="text/javascript">
    function format_number(n){
        var b=parseInt(n).toString();
        var len=b.length;
        if(len<=3){return b;}
        var r=len%3;
        return r>0?b.slice(0,r)+","+b.slice(r,len).match(/\d{3}/g).join(","):b.slice(r,len).match(/\d{3}/g).join(",");
    }

    var a="53669988.000";
    alert(format_number(a));
    alert(format_number("wahh"));
    alert(format_number(0));
    alert(format_number(6698.0023));
</script>