function fileList(id) {
  if(document.getElementById("content" + id).style.display == "block") {
    document.getElementById("content" + id).style.display = "none";
    document.getElementById("dir" + id).src = "./img/source/plus.png";
    document.getElementById("verz" + id).src = "./img/source/ext/dir0.gif";
  } else {
    document.getElementById("content" + id).style.display = "block";
    document.getElementById("dir" + id).src = "./img/source/minus.png";
    document.getElementById("verz" + id).src = "./img/source/ext/dir1.gif";
  }
}