function showhide1(tab_id_a){
  if(document.getElementById){
    if(document.getElementById(tab_id_a).style.display == "block"){
      document.getElementById(tab_id_a).style.display = "none";
    }else{
      document.getElementById("tab_id_a1").style.display = "none";
      document.getElementById("tab_id_a2").style.display = "none";
      document.getElementById(tab_id_a).style.display = "block";
    }
  }
}

function showhide2(tab_id_b){
  if(document.getElementById){
    if(document.getElementById(tab_id_b).style.display == "block"){
      document.getElementById(tab_id_b).style.display = "none";
    }else{
      document.getElementById("tab_id_b1").style.display = "none";
      document.getElementById("tab_id_b2").style.display = "none";
      document.getElementById(tab_id_b).style.display = "block";
    }
  }
}