js 小写金额转大写

    function smalltoBIG(n) {
            var fraction = ['角', '分'];
            var digit = ['零', '壹', '贰', '叁', '肆', '伍', '陆', '柒', '捌', '玖'];
            var unit = [
                ['元', '万', '亿'],
                ['', '拾', '佰', '仟']
            ];
            var head = n < 0 ? '欠' : '';
            n = Math.abs(n);

            var s = '';

            for (var i = 0; i < fraction.length; i++) {
                s += (digit[Math.floor(n * 10 * Math.pow(10, i)) % 10] + fraction[i]).replace(/零./, '');
            }
            s = s || '整';
            n = Math.floor(n);

            for (var i = 0; i < unit[0].length && n > 0; i++) {
                var p = '';
                for (var j = 0; j < unit[1].length && n > 0; j++) {
                    p = digit[n % 10] + unit[1][j] + p;
                    n = Math.floor(n / 10);
                }
                s = p.replace(/(零.)*零$/, '').replace(/^$/, '零') + unit[0][i] + s;
            }
            return head + s.replace(/(零.)*零元/, '元').replace(/(零.)+/g, '零').replace(/^整$/, '零元整');
        }
        console.log(smalltoBIG(99.89)); //玖拾玖元捌角玖分