HTMLOutputElement：labels 属性

<label id="label1" for="test">标签 1</label>
<output id="test">输出</output>
<label id="label2" for="test">标签 2</label>

window.addEventListener("DOMContentLoaded", () => {
  const output = document.getElementById("test");
  for (const label of output.labels) {
    console.log(label.textContent); // “标签 1”和“标签 2“
  }
});