使用地理位置选择REST服务器

function getDistanceFromLatLonInKm(lat1,lon1,lat2,lon2) { 
     var R = 6371; // Radius of the earth in km 
     var dLat = deg2rad(lat2-lat1); // deg2rad below 
     var dLon = deg2rad(lon2-lon1); 
     var a = Math.sin(dLat/2) * Math.sin(dLat/2) + Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2)) * Math.sin(dLon/2) * Math.sin(dLon/2); 
     var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); 
     var d = R * c; // Distance in km 
   return d; 
} 

function deg2rad(deg) {
    return deg * (Math.PI/180) 
}