> For the complete documentation index, see [llms.txt](https://docs.mapbox.com/mapbox-gl-js/llms.txt)
# Show polygon information on click
In this example, when a user clicks a polygon in a specified layer, the map shows a popup containing information about the clicked feature.
When the map loads, it uses [`addSource`](https://docs.mapbox.com/mapbox-gl-js/api/map/#map#addsource) and [`addLayer`](https://docs.mapbox.com/mapbox-gl-js/api/map/#map#addlayer) to add and style a layer called `states-layer`, which contains state polygons.
When the user clicks a feature in the `states-layer` layer, the example uses the [`Popup`](https://docs.mapbox.com/mapbox-gl-js/api/markers/#popup) method to create a new popup using [`MapMouseEvent`](https://docs.mapbox.com/mapbox-gl-js/api/events/#mapmouseevent) data to set the position and content of the popup.
Lastly, it uses the `Map` events [`mouseenter`](https://docs.mapbox.com/mapbox-gl-js/api/map/#map.event:mouseenter) and [`mouseleave`](https://docs.mapbox.com/mapbox-gl-js/api/map/#map.event:mouseleave) to toggle the user's cursor to a pointer while it hovers over any feature in `states-layer`.
> Example code:
**JavaScript**
```html
Show polygon information on click
```
**React**
```jsx
import React, { useEffect, useRef } from 'react';
import * as mapboxgl from 'mapbox-gl/esm';
import 'mapbox-gl/dist/mapbox-gl.css';
const MapboxExample = () => {
const mapContainerRef = useRef();
const mapRef = useRef();
useEffect(() => {
mapRef.current = new mapboxgl.Map({
// TO MAKE THE MAP APPEAR YOU MUST
// ADD YOUR ACCESS TOKEN FROM
// https://account.mapbox.com
accessToken: 'YOUR_MAPBOX_ACCESS_TOKEN',
container: mapContainerRef.current,
style: 'mapbox://styles/mapbox/standard',
center: [-100.04, 38.907],
zoom: 3
});
mapRef.current.on('load', () => {
mapRef.current.addSource('states', {
type: 'geojson',
data: 'https://docs.mapbox.com/mapbox-gl-js/assets/ne_110m_admin_1_states_provinces_shp.geojson'
});
mapRef.current.addLayer({
id: 'states-layer',
type: 'fill',
source: 'states',
paint: {
'fill-color': 'rgba(200, 100, 240, 0.4)',
'fill-outline-color': 'rgba(200, 100, 240, 1)'
}
});
mapRef.current.on('click', 'states-layer', (e) => {
new mapboxgl.Popup()
.setLngLat(e.lngLat)
.setHTML(e.features[0].properties.name)
.addTo(mapRef.current);
});
mapRef.current.on('mouseenter', 'states-layer', () => {
mapRef.current.getCanvas().style.cursor = 'pointer';
});
mapRef.current.on('mouseleave', 'states-layer', () => {
mapRef.current.getCanvas().style.cursor = '';
});
});
return () => mapRef.current.remove();
}, []);
return ;
};
export default MapboxExample;
```