var cur_step = 1;
var timer = 0;
function hiliteButton(num)
{
  // unhighlight all
  var i = 0;
  for (i=1;i<=4;i++) {
	document.getElementById('button'+i).className = 'button';
	document.getElementById('step'+i).style.display = 'none';
  }
  // highlight selected
	document.getElementById('button'+num).className = 'button_selected';
	document.getElementById('step'+num).style.display = 'block';
	if (num<4) {
		cur_step = num + 1
	} else {
	cur_step = 1;
	}
	if (timer) {
		clearTimeout(timer);
	}
	timer = setTimeout('hiliteButton('+cur_step+')',5000);
}
hiliteButton(1);