Once in Google Maps, click on the map (Do not click on markers) a popup should show at the bottom with the place and the coordinates displayed in the last line. If everything works as expected you should see a line of text on top of the map with the confirmation of the coordinates been copied to clipboard. Press Control + Shift + L while on streetview to get the coordinates from the URL. (Doesn't work on Firefox)
Thanks, it's a useful script. On line 44, it should be '.. && newLatLng.length > 0'.