var flagNav = new Array(4);

flagNav[0] = new Image();
flagNav[0].src = "buttons/eng_off.jpg";
flagNav[1] = new Image();
flagNav[1].src = "buttons/eng_on.jpg";
flagNav[2] = new Image();
flagNav[2].src = "buttons/ger_off.jpg";
flagNav[3] = new Image();
flagNav[3].src = "buttons/ger_on.jpg";

function flag(strImg,nButton) {
		document.images[strImg].src = flagNav[nButton].src;
}