go between latin and cyrillic on your chrome browser (for serbo-croatian language)
download this project as a .zip and then unfold it so that it's a folder
to install, go to chrome://extensions/ and click 'developer mode' in the top right. then 'load unpacked extension' and put in the folder from this project. should be straight-forward
just activate it by typing [-] for latin and [+] for cyrillic