Baseline Widely available *
The ShadowRoot
interface of the Shadow DOM API is the root node of a DOM subtree that is rendered separately from a document's main DOM tree.
You can retrieve a reference to an element's shadow root using its Element.shadowRoot
property, provided it was created using Element.attachShadow()
with the mode
option set to open
.
ShadowRoot.activeElement
Read only
Returns the Element
within the shadow tree that has focus.
ShadowRoot.adoptedStyleSheets
Add an array of constructed stylesheets to be used by the shadow DOM subtree. These may be shared with other DOM subtrees that share the same parent Document
node, and the document itself.
ShadowRoot.clonable
Read only
A boolean that indicates whether the shadow root is clonable.
ShadowRoot.delegatesFocus
Read only
A boolean that indicates whether the shadow root delegates focus if a non-focusable node is selected.
ShadowRoot.fullscreenElement
Read only
The element that's currently in full screen mode for this shadow tree.
ShadowRoot.host
Read only
Returns a reference to the DOM element the ShadowRoot
is attached to.
ShadowRoot.innerHTML
Sets or returns a reference to the DOM tree inside the ShadowRoot
.
ShadowRoot.mode
Read only
The mode of the ShadowRoot
, either open
or closed
. This defines whether or not the shadow root's internal features are accessible from JavaScript.
ShadowRoot.pictureInPictureElement
Read only
Returns the Element
within the shadow tree that is currently being presented in picture-in-picture mode.
ShadowRoot.pointerLockElement
Read only
Returns the Element
set as the target for mouse events while the pointer is locked. null
if lock is pending, pointer is unlocked, or if the target is in another tree.
ShadowRoot.serializable
Read only
A boolean that indicates whether the shadow root is serializable. A serializable shadow root inside an element will be serialized by Element.getHTML()
or ShadowRoot.getHTML()
when its options.serializableShadowRoots
parameter is set true
. This is set when the shadow root is created.
ShadowRoot.slotAssignment
Read only
Returns a string containing the type of slot assignment, either manual
or named
.
ShadowRoot.styleSheets
Read only
Returns a StyleSheetList
of CSSStyleSheet
objects for stylesheets explicitly linked into, or embedded in a shadow tree.
ShadowRoot.getAnimations()
Returns an array of all Animation
objects currently in effect, whose target elements are descendants of the shadow tree.
ShadowRoot.getSelection()
Non-standard
Returns a Selection
object representing the range of text selected by the user, or the current position of the caret.
ShadowRoot.elementFromPoint()
Non-standard
Returns the topmost element at the specified coordinates.
ShadowRoot.elementsFromPoint()
Non-standard
Returns an array of all elements at the specified coordinates.
ShadowRoot.setHTMLUnsafe()
Parses a string of HTML into a document fragment, without sanitization, which then replaces the shadowroot's original subtree. The HTML string may include declarative shadow roots, which would be parsed as template elements the HTML was set using ShadowRoot.innerHTML
.
The following events are available to ShadowRoot
via event bubbling from HTMLSlotElement
:
HTMLSlotElement
slotchange
event
An event fired when the node(s) contained in that slot change.
The following snippets are taken from our life-cycle-callbacks example (see it live also), which creates an element that displays a square of a size and color specified in the element's attributes.
Inside the <custom-square>
element's class definition we include some life cycle callbacks that make a call to an external function, updateStyle()
, which actually applies the size and color to the element. You'll see that we are passing it this
(the custom element itself) as a parameter.
class Square extends HTMLElement {
// â¦
connectedCallback() {
console.log("Custom square element added to page.");
updateStyle(this);
}
attributeChangedCallback(name, oldValue, newValue) {
console.log("Custom square element attributes changed.");
updateStyle(this);
}
// â¦
}
In the updateStyle()
function itself, we get a reference to the shadow DOM using Element.shadowRoot
. From here we use standard DOM traversal techniques to find the <style>
element inside the shadow DOM and then update the CSS found inside it:
function updateStyle(elem) {
const shadow = elem.shadowRoot;
const childNodes = shadow.childNodes;
for (const node of childNodes) {
if (node.nodeName === "STYLE") {
node.textContent = `
div {
width: ${elem.getAttribute("l")}px;
height: ${elem.getAttribute("l")}px;
background-color: ${elem.getAttribute("c")};
}
`;
}
}
}
Specifications Browser compatibility
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HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.3