function activateDetailsSection(section_name) {  
  hideDetailsSection("kurs");
  hideDetailsSection("ort");
  hideDetailsSection("zeit");
  hideDetailsSection("dozent");
  hideDetailsSection("foto");
  hideDetailsSection("sonstiges");
  
  showDetailsSection(section_name);
}

function showDetailsSection(section_name) {
  var tab_element  = document.getElementById("tab_" + section_name);
  var body_element = document.getElementById("details_body_" + section_name);
  tab_element.className += " aktiv";
  body_element.className += " aktiv";
}

function hideDetailsSection(section_name) {
  var tab_element  = document.getElementById("tab_" + section_name);
  var body_element = document.getElementById("details_body_" + section_name);
  tab_element.className = tab_element.className.replace("aktiv", "");
  body_element.className = body_element.className.replace("aktiv", "");
}