function tabLoad(){
    document.getElementById("tab1").style.display = "block";
    document.getElementById("tab2").style.display = "none";
    document.getElementById("tab3").style.display = "none";
    document.getElementById("tab4").style.display = "none";
  }
  function tabChange(tabId){
    tab = document.getElementById("tab" + tabId);
    tab.style.display = "block";
    switch(tabId){
      case 1:
        document.getElementById("tab2").style.display = "none";
        document.getElementById("tab3").style.display = "none";
        document.getElementById("tab4").style.display = "none";
        break;
      case 2:
        document.getElementById("tab1").style.display = "none";
        document.getElementById("tab3").style.display = "none";
        document.getElementById("tab4").style.display = "none";
        break;
      case 3:
        document.getElementById("tab1").style.display = "none";
        document.getElementById("tab2").style.display = "none";
        document.getElementById("tab4").style.display = "none";
        break;
      case 4:
        document.getElementById("tab1").style.display = "none";
        document.getElementById("tab2").style.display = "none";
        document.getElementById("tab3").style.display = "none";
        break;
    }
  }