_root level Button properties

I just need to know how to set the on (whatever) for an instanced button in the _root level

I figured it would work like this (“link” being the name of the buttons instance)

[FONT=Courier New]_root.link.on (release){
getURL(url_obj, “_blank”)
}[/FONT]

I get an error on test

[FONT=Courier New]Expected a field name after ‘.’ operator.
_root.link.on (release){[/FONT]

I’m working in MX but would prefer output in 5