function font_size(s){
    
    s = s*10;
    
    
    if(!(fs = loadCookie('fs'))){
        fs = 100;
        document.cookie = "fs=100" ; //クッキーへの書き込み
    }
    
    
    fs = fs*1 + s*1;
    
    if(fs<20) fs = 20;
    if(fs>150) fs = 150;
    
    document.cookie = "fs="+fs ; //クッキーへの書き込み
    
    
    //document.cookie = "fs=100";	// クッキーのリセット
    
    //alert(fs);
    window.location.reload()
}



function loadCookie(arg){ //argはデータ識別文字列
    if(arg){
        cookieData = document.cookie + ";" //文字列の最後に「;」を追加
        startPoint1 = cookieData.indexOf(arg);
        startPoint2 = cookieData.indexOf("=",startPoint1);
        endPoint = cookieData.indexOf(";",startPoint1);
        if(startPoint2 < endPoint && startPoint1 > -1){
            cookieData = cookieData.substring(startPoint2+1,endPoint);
            cookieData = cookieData;
            return cookieData
        }
    }
    return false
}