var currentSection = "";
var openSection    = "no_docentes";

Event.observe(window, "load", function() {
  if (openSection != "" && $(openSection + "-children"))
    $(openSection + "-children").removeClassName("hidden");
});

function showOrCollapseSection(sectionName)
{
  if (sectionName == openSection)
    return false;

  if (currentSection == sectionName) {
    collapseSection(sectionName);
  } else {
    if ((currentSection != "") && ($(currentSection + "-children")))
      collapseSection(currentSection);
    showSection(sectionName);
  }

  return false;
}

function showSection(sectionName) {
  var section  = $(sectionName);
  var children = $(sectionName + "-children");
  var arrow    = $(sectionName + "-arrow");
  var anchor   = $(sectionName + "-anchor");
  var path     = "http://www.unlp.edu.ar./images/arrow_black.png";

  section.toggleClassName("selected");
  anchor.toggleClassName("selected");
  arrow.src = path;
  arrow.alt = "-";
  children.toggleClassName("hidden");

  currentSection = sectionName;
}

function collapseSection(sectionName) {
  var section  = $(sectionName);
  var children = $(sectionName + "-children");
  var anchor   = $(sectionName + "-anchor");
  var arrow    = $(sectionName + "-arrow");
  var path     = "http://www.unlp.edu.ar./images/arrow_white.png";

  section.toggleClassName("selected");
  anchor.toggleClassName("selected");
  arrow.src = path;
  arrow.alt = "+";
  children.toggleClassName("hidden");

  currentSection = "";
}