ScrollPane Zooming - Help!

[ale_jrb]

Hi,
I have set up a scrollpane with an image and I'm trying to make it zoom in, but its not working. I think I've made a mistake in my function syntax but I'm not sure what it would be.

Here's the code:
// Zooming function

function zoomIn() {
ScrollPane.scrollframe.content._xscale += 1;
ScrollPane.scrollframe.content._yscale += 1;
}

function zoomOut() {
ScrollPane.scrollframe.content._xscale -= 1;
ScrollPane.scrollframe.content._yscale -= 1;
}

plus_btn.addEventListener("click", zoomIn);
minus_btn.addEventListener("click", zoomOut);

I'm also not toally sure what the items should be to make it zoom. ScrollPane is the name of my scrollpane, but do I need to replace it with the name of the image or soemthing?

Help. Thanks :).