Using GeometryUtil.js to compute distances between markers on a Leaflet map

GeometryUtil.js_Closest_snippet

// while we're at it, find the closest marker to user
  closest = L.GeometryUtil.closest(map3, points, myLL);

  for (i = 0; i < points.length; i++) {
    var delta = 1E-14;
    var latDiff = Math.abs(points[i].lat - closest.lat);
    var lngDiff = Math.abs(points[i].lng - closest.lng);
    if (((latDiff < delta) && (lngDiff < delta))) {
      closestIdx = i;
      closestDist = myLL.distanceTo(points[i]);
      break;   // if 2 markers are identical-enough, only return 1st
    }
  }

  // output results of nearest marker
  x = document.getElementById('nearestMarker');
  x.className = 'highlighted';
  x.innerHTML = 'NEAREST MARKER<br>Name: ' + points[closestIdx].name +
    '<br>Latitude: ' + points[closestIdx].lat +
    '<br>Longitude: ' + points[closestIdx].lng +
    '<br>Distance: ' + (Math.round(10 * (closestDist / 1000)) / 10) +
    ' km / ' + (Math.round(10 * (closestDist / 1609.34)) / 10) + ' mi';