Problem playing project in google chrome

There is a tank game online.

I opened the game on two tabs in google chrome.

And played for two players.

When the first player moves, the second player on the other tab should see it.

But if after the movement of the first player I do not click on the second tab, then I will not see the movement from the first player.

I have to click on the window of the second tab of the browser to see the updated last position of the player. Thanks in advance

Here is the video

youtube.com/watch