Timer is paused on changing the tab in Chrome

My Pomodro clock timer is getting paused when I am changing the tab.Why it’s happening and what is the solution so that it doesn’t get paused on changing the tab.
Here is the link of my Pomodoro Timer
Project Link - https://codepen.io/FaizAhmadF/full/EyybWX/6

set log in

>   function updateTimer() {
> 		  console.log("tenMilisec: " + tenMilisec);

And open cosole and click 3 dots right and select icon for undocking your dev tools
Then looks how it smooth goes every 10ms when your focus is on tab
but when change it goes one for every second

Here u have explanation: