function show_tab(tab) {
  if (tab == "tab-1") {
    document.getElementById("tab-1").style.display="block";
    document.getElementById("tab-2").style.display="none";
    document.getElementById("tab-3").style.display="none";
    document.getElementById("tab-4").style.display="none";
    document.getElementById("tab-5").style.display="none";
  }
  if (tab == "tab-2") {
    document.getElementById("tab-1").style.display="none";
    document.getElementById("tab-2").style.display="block";
    document.getElementById("tab-3").style.display="none";
    document.getElementById("tab-4").style.display="none";
    document.getElementById("tab-5").style.display="none";
  }
  if (tab == "tab-3") {
    document.getElementById("tab-1").style.display="none";
    document.getElementById("tab-2").style.display="none";
    document.getElementById("tab-3").style.display="block";
    document.getElementById("tab-4").style.display="none";
    document.getElementById("tab-5").style.display="none";
  }
  if (tab == "tab-4") {
    document.getElementById("tab-1").style.display="none";
    document.getElementById("tab-2").style.display="none";
    document.getElementById("tab-3").style.display="none";
    document.getElementById("tab-4").style.display="block";
    document.getElementById("tab-5").style.display="none";
  }
  if (tab == "tab-5") {
    document.getElementById("tab-1").style.display="none";
    document.getElementById("tab-2").style.display="none";
    document.getElementById("tab-3").style.display="none";
    document.getElementById("tab-4").style.display="none";
    document.getElementById("tab-5").style.display="block";
  }
  
}

function prepare_tabs() {
   var links = document.getElementsByTagName("a");
   for (var i=0; i < links.length; i++){
      links[i].onclick = function(){
         var destination = this.getAttribute("href");
         if (destination.indexOf("#tab1") != -1){ show_tab('tab-1'); }
         if (destination.indexOf("#tab2") != -1){ show_tab('tab-2'); }
         if (destination.indexOf("#tab3") != -1){ show_tab('tab-3'); }
         if (destination.indexOf("#tab4") != -1){ show_tab('tab-4'); }
         if (destination.indexOf("#tab5") != -1){ show_tab('tab-5'); }
      }
   }
}

add_load_event(prepare_tabs);