Need Help (full screen)

In this AS, mc_bground works but not mc_content. can anyone help me out please.

stop ();
Stage.align = “TL”;
Stage.scaleMode = “noScale”;

sizeListener = new Object();
sizeListener.onResize = doResize;
Stage.addListener({onResize:doResize});

function doResize() {
mc_bground._height = Stage.height;
mc_bground._width = Stage.width;
mc_content._x = Math.floor((Stage.width - mc_content._width) / 2);
mc_content._y = Math.floor((Stage.height - mc_content._height) / 2);

};
Stage.addListener(sizeListener);
doResize();