我如何在這個函數中定位其他元素(除了body)？這樣做有可能嗎？

因此，該功能允許我使用按鈕切換暗/亮主題，與body元素一起工作很好，但如果我試圖包含任何其他元素，與body包含的方式相同，它不適用。

(function() {
    let onpageLoad = localStorage.getItem("tema") || "";
    let element = document.body;
    element.classList.add(onpageLoad);
    document.getElementById("tema").textContent =
      localStorage.getItem("tema") || "light";
})();
  
  function promeniTemu() {
    let element = document.body;
    element.classList.toggle("svetlaTema");
    let tema = localStorage.getItem("tema");
    if (tema && tema === "svetlaTema") {
      localStorage.setItem("tema", "");
    } else {
      localStorage.setItem("tema", "svetlaTema");
    }
  
    document.getElementById("tema").textContent = localStorage.getItem("tema");
  }```

querySelector seems to work, but if I use it for example on a header, the theme doesn't save on other pages, it refreshes, but if its only the body being changed theme works normally and saves everytime.

使用querySelector代替getElementById是可行的。