Does Sugarcube 2 have a "check" function?

I have a variable that counts down from 1000 to 0 in ten seconds. I also have a <<if $var is 0>> condition at the bottom of the page, however that only registers when the page loads in, and $var is at 1000.

Is there a check function or something I can do to make the program say "Hey, $var is now 0, you wanna run that bit of conditional code now?"

Any help would be greatly appreciated.

Edit: I'm aware reloading the page does that, but that would just reload the counter up to 1000, show the thing that should be available only when it's at 0... and basically break everything.