dollarAmountInWords.js

function toWords(s) {
	s = s.toString();
	s = s.replace(/[\, ]/g, '');
	if (s != parseFloat(s)) return 'not a number';
	var x = s.indexOf('.');
	if (x == -1) x = s.length;
	if (x > 15) return 'too big';
	var n = s.split('');
	var str = '';
	var sk = 0;
	for (var i = 0; i < x; i++) {
		if ((x - i) % 3 == 2) {
			if (n[i] == '1') {
				str += tn[Number(n[i + 1])] + ' ';
				i++;
				sk = 1;
			} else if (n[i] != 0) {
				str += tw[n[i] - 2] + ' ';
				sk = 1;
			}
		} else if (n[i] != 0) {
			str += dg[n[i]] + ' ';
			if ((x - i) % 3 == 0) str += 'hundred ';
			sk = 1;
		}
		if ((x - i) % 3 == 1) {
			if (sk) str += th[(x - i - 1) / 3] + ' ';
			sk = 0;
		}
	}

	str += 'dollars';

	if (x != s.length) {
		var y = s.length;
		str += ' and ';
		for (var i = x + 1; i < y; i++) {
			if (n[i]  < 2) {
				if (n[i] == 1) {
					i++;
					str += tn[n[i]] + ' ';
				} else {
					i++
					str += 'zero';
				}
			} else {
				str += (n[i] != 0 ? tw[n[i] - 2] + ' ' : '');
				i++;
				str += (n[i] != 0 ? dg[n[i]] + ' ' : '');
			}
		}
		str += ' cents'
	}
	return str.replace(/\s+/g, ' ');
}