document.querySelectorAll(".floating>input").forEach(e => {
   function checkState() {
      if (e.value !== "") {
         if (e.classList.contains("used")) return;
         e.classList.add("used")
      } else {
         if (e.classList.contains("used")) e.classList.remove("used")
      }
   }

   e.addEventListener("change", () => checkState())
   checkState()
})