Trying to better handle leaving and coming back to a web game (how do we capture that?)

Hi there, so I was noticing how a web game freezes till you come back. this is fine, but i don't like how my game behaves upon return. I thought it would be nice to perhaps have it do a fade from black upon return..

I have a FPS / filter event sheet that works well when you first come to the site, but because of the jerk in cpu between tabs this temporarily breaks the effect and giving it a fade from black when you click the tab again to return would be cool.

I just don't know what to call that moment in the game.. is it the browser "offline" events?

Probably system -> on resumed.

There is also system -> on suspended