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="lion";
		tIDObj.className="lioff";
  	tIDObj_content.style.display='none';
  	IDObj_content.style.display='block';
    	tID=ID;
    }
}