How to know if client is done with fading gui?

Hello i would like to know how to let the server know the client is done fading the gui if it's even possible or do i just have to use a wait(7) and hope the client is done fading

I have the remote and fade script i just wanna know how i can let the server know the client is done fading a gui

--CLIENT
game.ReplicatedStorage:WaitForChild("js").OnClientEvent:Connect(function(fade)
for i = 1,10 do
fade = fade - 1
end
end)

-- SERVER
local fade = 10
game.ReplicatedStorage.js:FireAllClients(fade)
repeat wait() until fade == 0
print"all clients done fading!"

wont work ;'/