强制保留小数点后两位

    function toDecimal2(x) {
        var f = parseFloat(x);
        if (isNaN(f)) {
            return false;
        }
        var f = Math.round(x * 100) / 100;
        var s = f.toString();
        var rs = s.indexOf('.');
        if (rs < 0) {
            rs = s.length;
            s += '.';
        }
        while (s.length <= rs + 2) {
            s += '0';
        }
        return s;
    }