function opendiv(o){
	 var id;
	 var e;
	 for(var i=1;i<=3;i++){
	   id ="cat"+i;
	   e = document.getElementById("cat_con"+i);
	   if(id != o.id){
	   	 e.style.display = "none";
	   }else{
		 e.style.display = "block";
	        }
	   }
      }
var tID = "nav1";
function showmenu(ID){
  if(ID!=tID){
	var IDObj = document.getElementById( ID );
	var tIDObj = document.getElementById( tID );
	var IDObj_content = document.getElementById( ID + "_" );
	var tIDObj_content = document.getElementById( tID + "_" );
    	IDObj.className='nav_link_02';
    	tIDObj.className='nav_link_01';
  	tIDObj_content.style.display='none';
  	IDObj_content.style.display='';
    	tID=ID;
  }
}