Geocoordinates lat long distance

dist.js

/**
 * returns the distance between two lat long coordinates
 * (uses degToRad and radToDeg functions below)
 */
function latlongdist(lat1, long1, lat2, long2) {
    var theta = long1 - long2;
    var miles = (Math.sin(degToRad(lat1)) * Math.sin(degToRad(lat2))) + (Math.cos(degToRad(lat1)) * Math.cos(degToRad(lat2)) * Math.cos(degToRad(theta)));
    miles = radToDeg(Math.acos(miles)) * 60 * 1.1515;
    var feet = miles * 5280;
    var yards = feet / 3;
    var km = miles * 1.609344;
    var meters = km * 1000;
    return {
      'miles':miles,
      'feet':feet,
      'yards':yards,
      'km':km,
      'meters':meters
    }; 
}