lat and lng can't set, because is null

_wrong_var.js

  var lat = document.getElementById("lat");
  var lng = document.getElementById("long");
  function getLocation() {
    if (navigator.geolocation) {
      navigator.geolocation.getCurrentPosition(
        addPositionHandler,
        errorHandler,
        {highAccuracy: false,
         maximumAge: 30000, // 30 seconds
         timeout: 60000 // 1 minute
        });
    }
  };

  function errorHandler(err) {
    console.warn('ERROR(' + err.code + '): ' + err.message);
  };

  function addPositionHandler(position) {
    var crd = position.coords;
    var plat = crd.latitude;
    var plong = crd.longitude;
    lat.value = plat; // lat is null
    lng.value = plong; // lng is null
    console.log('Lat: ' + plat + ' Long: ' + plong);
  };

fixed.js

  function getLocation() {
    if (navigator.geolocation) {
      navigator.geolocation.getCurrentPosition(
        addPositionHandler,
        errorHandler,
        {highAccuracy: false,
         maximumAge: 30000, // 30 seconds
         timeout: 60000 // 1 minute
        });
    }
  };

  function errorHandler(err) {
    console.warn('ERROR(' + err.code + '): ' + err.message);
  };

  function addPositionHandler(position) {
    var crd = position.coords;
    document.getElementById("lat").value = crd.latitude;
    document.getElementById("long").value = crd.longitude;
  };