Leaflet map-event 'load' does not fire

Or use inline

var mymap = L.map('YOUR_MAP_ID').on('load', onMapLoad).setView([51.505, -0.09], 13);

function onMapLoad(){
  console.log("map loaded");
}

I suggest you to use the "whenReady" method available in Leaflet 1.0.1

var callBack = function () {
    console.log("Map successfully loaded");
    // do some stuff
};

mymap.whenReady(callBack);

Put the mymap.on('load', onMapLoad); event handler before you actually load the map (with map.setView...).

So your actual code should look like,

var mymap = L.map('mapid');
mymap.on('load', onMapLoad);
mymap.setView([51.505, -0.09], 13);

Source : Github Issue