Shadow tree A DOM element can have two types of DOM subtrees: Light tree – a regular DOM subtree, made of HTML children. All subtrees that we’ve seen in previous chapters were “light”. Shadow tree – a hidden DOM subtree, not reflected in HTML, hidden from prying eyes.
Shadow DOM elements: Have their own ids space, Invisible to JavaScript selectors from the main document, such as querySelector, Use styles only from the shadow tree, not from the main document.
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