function bulletStart() {
        current_page = null
        f_show_page("StartPage")
        document.getElementById("navbar").style.visibility = ""
      }
      function f_show_page(page) {
        if (current_page != null) {
          document.getElementById("Page/" + current_page).style.visibility = "hidden"
          document.getElementById("Bullet/" + current_page).style.color = "#999999"
        }
        // document.getElementById("Page/" + page).style.visibility = ""
        document.getElementById("Bullet/" + page).style.color = "red"
        current_page = page
      }