can you do this without on clicked handler?

Hey, I found this script while searching through the forums and I found this code to scroll through text in a text field.

on clicked the_object
	set object_name to name of the_object as Unicode text
	if object_name = "scroll" then
		tell text field "scroll_text" of window "main"
			set the_string to string value
			repeat with i from 1 to (count the_string)
				set string value to the_string's text i thru -1
				delay 0.1
			end repeat
			set string value to the_string
		end tell
	end if
end clicked

I figured that if I put it inside an on idle handler (something like this)

on idle theObject
	tell text field "scroll_text" of window "main"
		set the_string to string value
		repeat with i from 1 to (count the_string)
			set string value to the_string's text i thru -1
			delay 0.1
		end repeat
		set string value to the_string
	end tell
end idle

that it would scroll on its own…but it didnt work…anyone know how to do it?