How to acsess a local palyers humanoid to display his health in a gui?

Here's how to access the players humanoid's health:

local player = game.Players.LocalPlayer
local character = player.Character or player.CharacterAdded:Wait()
local humanoid = character:WaitForChild("Humanoid")

function onHealthChanged(newHealth)
    --Do whatever you want with the newHealth here
end

player.CharacterAdded:Connect(function(char)
    local character = char
    local humanoid = char:WaitForChild("Humanoid")
    healthChanged:Disconnect()
    healthChanged = humanoid.HealthChanged:Connect(onHealthChanged)
end)

local healthChanged = humanoid.HealthChanged:Connect(onHealthChanged)