JavaScript: Date Calculation + Date Parser

date.js

/************************************************************************
			Calculate Number of Days in Date Range
************************************************************************/
	function days_between(date1, date2) {

		var d1 = parseDate(date1.replace(/\-/g,'.'));
		var d2 = parseDate(date2.replace(/\-/g,'.'));

		// The number of milliseconds in one day
		var ONE_DAY = 1000 * 60 * 60 * 24;

		// Calculate the difference in milliseconds
		var difference_ms = Math.abs(d2 - d1);

		// Convert back to days and return
		return Math.round(difference_ms/ONE_DAY) + 1;
	}

	// Date Prser for Safari
	function parseDate(input, format) {
		format = format || 'yyyy-mm-dd'; // default format
		var parts = input.match(/(\d+)/g),
		i = 0, fmt = {};
		// extract date-part indexes from the format
		format.replace(/(yyyy|dd|mm)/g, function(part) { fmt[part] = i++; });

		return new Date(parts[fmt['yyyy']], parts[fmt['mm']]-1, parts[fmt['dd']]);
	}