How to get the name of a specific frame

one frame is named open, and one is named close.
how to detect in what frame the MC stopped.
i made this, “abo_btn” is one of buttons, but don’t know the script within if condition, “content” is the MC I want to control:

abo_btn.onRelease = function() {

_root.content.onEnterFrame = function() {

if (??? == “open”) {
} else {