Can't get location of status sent from browser


Hi, I create simple apps that do request to users/lookup, I intend to get location of their latest status, when I test create a status from my phone, everything is ok, But by tweeting my own status form browser (firefox v34), I get status.coordinates with value NULL. Is it suppose to be like that ? I can only get location from phone-based tweets ? Or is there any other requirements ? thanks.