TestPage = {}

local maxHp = 100
local currentHp = 100

function TestPage.Damage(event)

    currentHp = currentHp - 5

    local document = event.current_element.owner_document
    local target = document:GetElementById("hp-bar")

    if target then
        target:SetAttribute("current", currentHp)
    end

end

function TestPage.Heal(event)
    currentHp = currentHp + 5

    local document = event.current_element.owner_document
    local target = document:GetElementById("hp-bar")

    if target then
        target:SetAttribute("current", currentHp)
    end
end