calculate full years number between two dates

fullYearsBetween.js

yearsBetween = function(d1, d2, roundUp) {
	// dates parsing by sugarjs
	var d1 = Date.create(d1);
	var d2 = Date.create(d2);

	var range = d2.getFullYear() - d1.getFullYear();
	if (d2.setFullYear(1972) < d1.setFullYear(1972)) range--;
	
	if (roundUp && d2.getTime() !== d1.getTime()) range++;
	return range;
};