content.js

function cleanHeatmap() {
	map.removeLayer(heatmap);
}

function showHeatmap(heatdata, maxValue) {
	if (heatmap === null) {
		heatmap = L.heatLayer(heatdata, 
		{radius: 35, max: maxValue / ratio,
		blur: 25,
		gradient: {0.0: 'blue', 0.5: 'lime', 1: 'red'}
		}).addTo(map);
	} else {
		cleanHeatmap();
	}
	
	return heatmap;
}