Applescript: Trim the last three characters from text input

trim_last_3_chars.applescript

on run {input, parameters}
	set output to ((characters 1 thru -4 of (item 1 of input as string)) as string)
	--set output to (item 1 of input as string)
	(* Your script goes here *)
	(* if output ends with ".js" then
		set output to ((characters 1 thru -4 of output) as string)
		--display dialog updated
	end if
	*)
	--display dialog output
	--replace_text(input, ".js", "")
	return output
end run