This is a simple Chrome/Vivaldi extension to keep track of your stamina in Puzzle and Dragons. Your stamina is indicated on the extension's button. The timer also allows you to set push notification alerts when you have a certain amount of stamina, or at a certain time of day.
Drag the .crx file from the dist folder onto the extensions page. Alternatively you can build the extension yourself by running
npm install
gulp sassand then loading the unpacked extension from the extensions page.