Haversine Formula Function (Distance between coordinates)

haversineKm.js

// coordinatesDistanceInKm(43.248268, -89.840309, 43.19071, -89.33684)
function coordinatesDistanceInKm(latitude1, longitude1, latitude2, longitude2)
{
	var earthRadiusInKm = 6373;
	var radianMultipler = Math.PI / 180

	var distanceLatitude = (latitude2 - latitude1) * radianMultipler;
	var distanceLongitude = (longitude2 - longitude1) * radianMultipler;
	var latitude1InRadians = latitude1 * radianMultipler;
	var latitude2InRadians = latitude2 * radianMultipler;

	var halfChordDistanceSquared = Math.pow(Math.sin(distanceLatitude / 2), 2) +  
	        Math.cos(latitude1InRadians) * Math.cos(latitude2InRadians) *   
	        Math.pow(Math.sin(distanceLongitude / 2), 2);   

	var angularDistanceInRadians = 2 * Math.asin(Math.sqrt(halfChordDistanceSquared));

	var haversineDistance = earthRadiusInKm * angularDistanceInRadians;

	return haversineDistance;
}

haversineMiles.js

// coordinatesDistanceInMiles(43.248268, -89.840309, 43.19071, -89.33684)
function coordinatesDistanceInMiles(latitude1, longitude1, latitude2, longitude2)
{
	var earthRadiusInMiles = 3960;
	var radianMultipler = Math.PI / 180

	var distanceLatitude = (latitude2 - latitude1) * radianMultipler;
	var distanceLongitude = (longitude2 - longitude1) * radianMultipler;
	var latitude1InRadians = latitude1 * radianMultipler;
	var latitude2InRadians = latitude2 * radianMultipler;

	var halfChordDistanceSquared = Math.pow(Math.sin(distanceLatitude / 2), 2) +  
	        Math.cos(latitude1InRadians) * Math.cos(latitude2InRadians) *   
	        Math.pow(Math.sin(distanceLongitude / 2), 2);   

	var angularDistanceInRadians = 2 * Math.asin(Math.sqrt(halfChordDistanceSquared));

	var haversineDistance = earthRadiusInMiles * angularDistanceInRadians;

	return haversineDistance;
}