function dspTopBlock(){
  var a=document.registrationForm.sip_id;
  var b=document.registrationForm.top_id;
  if (a.selectedIndex>=0){a.selectedIndex=-1;}
  if (b.selectedIndex>=0){b.selectedIndex=-1;}
  if (document.getElementsByName("topbox")[0].checked == true){
    document.getElementById("StandardBlock").style.display = "none";
    document.getElementById("TopBlock").style.display = "block";
    document.getElementById("TopAGB").style.display = "block";
  }else{
    document.getElementById("TopBlock").style.display = "none";
    document.getElementById("TopAGB").style.display = "none";
    document.getElementById("StandardBlock").style.display = "block";
  }
}