html

<label id="label1" for="test">Label 1</label>
<textarea id="test">Some text</textarea>
<label id="label2" for="test">Label 2</label>

js

window.addEventListener("DOMContentLoaded", () => {
  const textArea = document.getElementById("test");
  for (const label of textArea.labels) {
    console.log(label.textContent); // "Label 1" and "Label 2"
  }
});