Displaying properties of GeoJSON in popup on Leaflet?

The line where you create and bind your popup should have been included in the onEachFeature option of your L.geoJSON factory.

var layerGroup = L.geoJSON(data, {
  onEachFeature: function (feature, layer) {
    layer.bindPopup('<h1>'+feature.properties.f1+'</h1><p>name: '+feature.properties.f2+'</p>');
  }
}).addTo(map);

Demo: http://playground-leaflet.rhcloud.com/wuseg/1/edit?html,output

Having this line outside the factory makes it access your outer scope layer variable, which is actually the GeoJSON Layer Group that holds all the features from your GeoJSON data, therefore it tries to bind a popup on each of these features (in your case, there is only 1 marker, but it could be more).

Above all, it does not know any feature variable, which creates an error.

Build a simple popup content for any properties in a simple way, in one line:

var layer = L.geoJSON(data, {
 onEachFeature: function (f, l) {
   l.bindPopup('<pre>'+JSON.stringify(f.properties,null,' ').replace(/[{}"]/g,'')+'</pre>');
 }
}).addTo(map);

You can use below codes:

function onEachFeature(feature, layer) {
    // does this feature have a property named popupContent?
    if (feature.properties && feature.properties.Name && feature.properties.Lat && feature.properties.Lon) {
        layer.bindPopup(feature.properties.Name+"("+feature.properties.Lat+","+feature.properties.Lon+")",);
    }
}
/// for Show in map marker style and popup
    L.geoJSON(geojsonFeature, {
    pointToLayer: function (feature, latlng) {
        return L.circleMarker(latlng, geojsonMarkerOptions);
    }, 
    onEachFeature: onEachFeature

}).addTo(map);