The mode read-only property of the ShadowRoot specifies its mode — either open or closed. This defines whether or not the shadow root's internal features are accessible from JavaScript.

When the mode of a shadow root is "closed", the shadow root's implementation internals are inaccessible and unchangeable from JavaScript—in the same way the implementation internals of, for example, the <video> element are inaccessible and unchangeable from JavaScript.


A value defined in the ShadowRootMode enum — either open or closed.


  // We create a closed shadow root, that is not accessible
  let element = document.createElement("div");
  element.attachShadow({ mode: "closed" });
  element.shadowRoot // null as the shadow root is closed

  // We create an open shadow root, that is accessible
  let element2 = document.createElement("div");
  element2.attachShadow({ mode: "open" });
  console.log(`The shadow is ${element2.shadowRoot.mode}`) // logs "The shadow is open"
  element2.shadowRoot.textContent("Opened shadow") // The shadow is open, we can access it from outside


DOM Standard
# dom-shadowroot-mode

Browser compatibility

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