Mine

if (starter != "y") {
	dir = "l";
	starter = "y";
}
_root.onEnterFrame = function() {
	if (Key.isDown(Key.RIGHT) ) {
		_root.mario._xscale = -100;
		_root.mario.nextFrame();
		_root.mario._x += 7;
		dir = "r";
	}
		if (Key.isDown(Key.LEFT)) {
			_root.mario._xscale = +100;
			_root.mario.nextFrame();
			_root.mario._x += -7;
		}
			if (Key.isDown(Key.UP) && jump == "no") {
		starty = _root.mario._y;
		jump = "yes";
		jumpv = -10;
	}
	if (jump == "yes") {
		jumpv += 1;
		_root.mario._y += jumpv;
	}
	if (_root.mario._y>starty) {
		_root.mario._y = starty;
		jump = "no";
	}
};