function  change_nav(heath_center){
    for(var i=1;i<=8;i++){
        if(i==heath_center){
           document.getElementById("nav_item"+i).className="ppd";
           document.getElementById("kobe"+i).style.display="";
        }
        else{
            document.getElementById("nav_item"+i).className="";
            document.getElementById("kobe"+i).style.display="none";
        }
    }
}


function  hidden(num){
    for(var j=1;j<=8;j++){
        if(j==num){
           document.getElementById("nav_item"+j).className="ppd";
           document.getElementById("kobe"+j).style.display="none";
        }
        else{
            document.getElementById("nav_item"+j).className="";
            document.getElementById("kobe"+j).style.display="none";
        }
    }
}