Creating empty movieclip

how do i create an empty movie clip say, a rectangle, with only the outlines and no fill? the rectangle border will load at a position, say, (0,0), then when i mouseover on the other buttons, it will ease to their coordinates, but the length will change according to the text length
i wan to use it for my nav bar

wad i currently have is

onClipEvent(load) {
n = this.createEmptyMovieClip(“bar”,1);
n.beginFill(0xcccccc,100);
n.lineTo(0,5);
n.lineTo(-0.1,5);
n.lineTo(-0.1,0);
n.lineTo(0,0);
n.endFill();
n._y -= n.height;
}

i copied this source from somewhere…thanx in advance