function nextLevel(tid){
	if(document.getElementById('huhu'+tid).style.display == "block"){
    document.getElementById('huhu'+tid).style.display = "none";
    document.getElementById('img'+tid).src = "images/plus.gif";
  }else{
    document.getElementById('huhu'+tid).style.display = "block";
    document.getElementById('img'+tid).src = "images/minus.gif";
  }
}