A timer is considered as a technical type of clock through which we can measure time interval. We just need to set a specific time then the timer starts its count down. It can be said as a timer and also an hourglass.
Some Technical Detail
Some technical modes are available
If a user is navigating another tab it can still be visible from tab.
It has a colorful display with ringing alarms
If a user exceeds the timer it shows an elapsed time.
A user can start or remove the countdown with just a click from a mouse on computer screen.