var i;
var id;
var items = -1;
var id_prefix = "flash_replacement_";

function switchReplacement(imgNum)
{
  if (items < 0) {
    items = getItemsLength();
  }
    for (i = 0; i < items; i++) {
		if (i == imgNum) {
			document.getElementById(id_prefix + i).style.display = "block";
		} else {
			document.getElementById(id_prefix + i).style.display = "none";
		}
	}
}

function getItemsLength() {
  if (document.getElementById(id_prefix + '1') == null) {
    return 1;
  }
  else if (document.getElementById(id_prefix + '2') == null) {
    return 2;
  }
  else {
    return 3;
  }
}