How to check what type of text user typed?

I have a TextBox that needs to be a number.

How can I check if TextBox text type is only numbers? (maybe something like: if string.type(path) == "number"

function check(var)
	if tonumber(var) ~= "" and tonumber(var) ~= nil then
		return true
	end
end

check(23)

try this

Try this:

local textbox = script.Parent.TextBox

textbox.Changed:Connect(function()
local text = tonumber(textbox.Text)
	if text ~= nil then
		print(text)
	end
end)

If the text has any letter added, the if-then statement will prevent whatever you're trying to do from being fired.

To not let them type non-digit characters, you can use the string pattern %D+. It matches 1 or more occurrences of non digit characters.

With that in mind...

textbox.Text = textbox.Text:gsub("%D+", "")

will look for non digit characters and replace them with empty string "".

textbox:GetPropertyChangedSignal("Text"):Connect(function()
    textbox.Text = textbox.Text:gsub("%D+", "")
end)