function swapTesti(active) {
	for (i=1;i<=4;i++) {
		img = document.getElementById('btn_'+i);
		txt = document.getElementById('txt_'+i);
		if (i==active) {
			img.className = 'active';
			txt.style.display = 'block';
		} else {
			img.className = '';
			txt.style.display = 'none';
		}
	}
}