Tell user to refresh the page, if access to location has failed

at least in my local firefox on laptop, it would not prompt user again
until page was refreshed

src/views/HomeView.vue

@@ -11,6 +11,7 @@ export default {
         return {
             coordinates: null,
             loading: false,
+            locationAccessBlocked: false,
         }
     },
 
@@ -22,13 +23,19 @@ export default {
 
         useCurrentLocation() {
 
-            if (location.protocol == 'http:') {
-                alert("Sorry, this only works for secure sites.")
+            if (this.locationAccessBlocked) {
+                alert("You must refresh the page first, then try again.")
+                return
             }
 
             navigator.geolocation.getCurrentPosition(loc => {
                 this.coordinates = `${loc.coords.latitude},${loc.coords.longitude}`
                 this.loadCoordinates()
+            }, error => {
+                if (error.code == 1) { // PERMISSION_DENIED
+                    this.locationAccessBlocked = true
+                }
+                alert(`error.code = ${error.code}\n\n${error.message}`)
             })
         },