html模板中的数字保留两位小数

<script>
    //html模板中的数字保留两位小数
    function formatCurrency(num) {
        num = num.toString().replace(/\$|\,/g,'');
        if(isNaN(num))
            num = "0";
        sign = (num == (num = Math.abs(num)));
        num = Math.floor(num*100+0.50000000001);
        cents = num%100;
        num = Math.floor(num/100).toString();
        if(cents<10)
            cents = "0" + cents;
        for (var i = 0; i < Math.floor((num.length-(1+i))/3); i++)
            num = num.substring(0,num.length-(4*i+3))+','+
                    num.substring(num.length-(4*i+3));
        return (((sign)?'':'-') + num + '.' + cents);
    }
</script>