Show values in popup when click on Leaflet map with raster as input

I'm using the Leaflet map to visualize raster data (.tif). For now, I want to add popup to show values when clicking on the Leaflet map. Link source code (html) that I use: https://github.com/GeoTIFF/georaster-layer-for-leaflet-example/blob/master/examples/color-scale.html

By the way, I attached an image that I want after add popup

Thanks in advance, Tuan