AppleScript to toggle fn key

fn_toggle.applescript

tell application "System Preferences"
    set current pane to pane "com.apple.preference.keyboard"
end tell

tell application "System Events"
    if UI elements enabled then
        tell application process "System Preferences"
            repeat until exists tab group 1 of window "Keyboard"
                delay 0.5
            end repeat
            click radio button "Keyboard" of tab group 1 of window "Keyboard"
            click checkbox "Use F1, F2, etc. keys as standard function keys" of tab group 1 of window "Keyboard"
        end tell
        tell application "System Preferences" to quit
    else
        -- GUI scripting not enabled.  Display an alert
        tell application "System Preferences"
            activate
            set current pane to pane "com.apple.preference.security"
            display dialog "UI element scripting is not enabled. Please activate this app under Privacy -> Accessibility so it can access the settings it needs."
        end tell
    end if
end tell