Help withTextBox ?

function onClicked()

local player=script.Parent.Parent.Parent.Parent
local character=player.Character
local humanoid=character:findFirstChild("Humanoid")
local textBox=script.Parent.TextBox

local value=tostring(textBox.Text)
if value~=nil then
-- Code
end
end
script.Parent.ImageButton.MouseButton1Down:connect(onClicked)

would this be Compatible with both Letters and Numbers?