Javascript Number.toCurrency() to convert INT 1234567 to CURRENCY £1,2345.67

Javascript: Number.toCurrency()

/*
	@fliptopbox
	
	Format a number as a currency.
	eg. 12345.67 = £12,345.67

	usage examples:
	(1234567.899).toCurrency(); // 1,234,567

	(1234567.999).toCurrency(0); // 1,234,567
	(1234567.999).toCurrency(2); // 1,234,568.00
	(1234567.999).toCurrency(2, '£'); // £1,234,568.00
	(1234567.999).toCurrency(2, '£', ':'); // £1:234:568.00

*/
if(!Number.toCurrency) {
	Number.prototype.toCurrency = function (decimals, prefix, kdelim) {
		decimals = typeof decimals === 'number' ? Math.min(decimals, 2) : 0;
		prefix = prefix || ''; // the currency prefix eg. '$'
		kdelim = kdelim || ','; // thousand delimininator eg. ','
		var value = this,
			valueAsInt = parseInt(value, 10),
			valueAsFixed = value.toFixed(decimals),
			stringValue = String(decimals === 0 ? valueAsInt : valueAsFixed)
			rex = new RegExp(kdelim + '$');

		return (
			prefix + stringValue.split('').reverse().join('')
				.replace(/(\d{3})/g, function(m,a) { return a + kdelim}).replace(rex, '')
				.split('').reverse().join('')
		);
	};
}