Timely

This extension will display two stopwatches every time you open Facebook on the browser; one stopwatch will display how much time you have been spending since you opened Facebook in a tab (session time) and the other one will display the total spent time per day.

Both stopwatches will change color according to the time spent. The left stopwatch will turn red when the total time is more than 60 minutes and the right stopwatch when the session time is more than 15 minutes.