This is leaflet control to push content to be displayed within a leaflet map.
<link rel="stylesheet" href="https://unpkg.com/leaflet@1.7.1/dist/leaflet.css" />
<link rel="stylesheet" href="dist/leaflet-push-content-control.css" />
<script src="https://unpkg.com/leaflet@1.7.1/dist/leaflet.js"></script>
<script src="dist/leaflet-push-content-control.js"></script>
<script>
var map = L.map('map').setView([51.505, -0.09], 13);
// Add leaflet-push-content to map
var leafletPushContentControl = (new L.Control.LeafletPushContentControl({
position: 'bottomright',
cssClassName: 'my-control-class'
}));
leafletPushContentControl.addTo(map);
</script>
leafletPushContentControl.updateControl('Hello World!');