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
.
Properties
ShadowRoot.delegatesFocus
Read only- Returns a boolean that indicates whether delegatesFocus was set when the shadow was attached (see
Element.attachShadow()
). 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
— eitheropen
orclosed
. This defines whether or not the shadow root's internal features are accessible from JavaScript.
Properties included from DocumentOrShadowRoot
The ShadowRoot
interface includes the following properties defined on the DocumentOrShadowRoot
mixin. Note that this is currently only implemented by Chrome; other browsers still implement them on the Document
interface.
DocumentOrShadowRoot.activeElement
Read only- Returns the
Element
within the shadow tree that has focus. DocumentOrShadowRoot.styleSheets
Read only- Returns a
StyleSheetList
ofCSSStyleSheet
objects for stylesheets explicitly linked into, or embedded in a document.
Methods
The ShadowRoot
interface includes the following methods defined on the DocumentOrShadowRoot
mixin. Note that this is currently only implemented by Chrome; other browsers still implement them on the Document
interface.
DocumentOrShadowRoot.getSelection()
- Returns a
Selection
object representing the range of text selected by the user, or the current position of the caret. DocumentOrShadowRoot.elementFromPoint()
- Returns the topmost element at the specified coordinates.
DocumentOrShadowRoot.elementsFromPoint()
- Returns an array of all elements at the specified coordinates.
DocumentOrShadowRoot.caretPositionFromPoint()
- Returns a
CaretPosition
object containing the DOM node containing the caret, and caret's character offset within that node.
Examples
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.
connectedCallback() { console.log('Custom square element added to page.'); updateStyle(this); } attributeChangedCallback(name, oldValue, newValue) { console.log('Custom square element attributes changed.'); updateStyle(this); }
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) { var shadow = elem.shadowRoot; var childNodes = shadow.childNodes; for(var i = 0; i < childNodes.length; i++) { if(childNodes[i].nodeName === 'STYLE') { childNodes[i].textContent = 'div {' + 'width: ' + elem.getAttribute('l') + 'px;' + 'height: ' + elem.getAttribute('l') + 'px;' + 'background-color: ' + elem.getAttribute('c') + ';' + '}'; } } }
Specifications
Specification | Status | Comment |
---|---|---|
DOM The definition of 'Interface ShadowRoot' in that specification. |
Living Standard |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
ShadowRoot | Chrome Full support 57 | Edge Full support 79 | Firefox
Full support
63
| IE No support No | Opera Full support 40 | Safari Full support 10.1 | WebView Android Full support 57 | Chrome Android Full support 57 | Firefox Android
Full support
63
| Opera Android Full support 41 | Safari iOS Full support 10.3 | Samsung Internet Android Full support 6.0 |
delegatesFocus | Chrome Full support 57 | Edge Full support 79 | Firefox ? | IE No support No | Opera ? | Safari No support No | WebView Android Full support 57 | Chrome Android Full support 57 | Firefox Android ? | Opera Android ? | Safari iOS No support No | Samsung Internet Android Full support 7.0 |
Features included from the DocumentOrShadowRoot mixin | Chrome Full support 57 | Edge Full support 79 | Firefox Full support 63 | IE No support No | Opera Full support 40 | Safari
No support
No
| WebView Android Full support 57 | Chrome Android Full support 57 | Firefox Android Full support 63 | Opera Android Full support 41 | Safari iOS
No support
No
| Samsung Internet Android Full support 6.0 |
host | Chrome Full support 57 | Edge Full support 79 | Firefox
Full support
63
| IE No support No | Opera Full support 40 | Safari Full support 10.1 | WebView Android Full support 57 | Chrome Android Full support 57 | Firefox Android
Full support
63
| Opera Android Full support 41 | Safari iOS Full support 10.3 | Samsung Internet Android Full support 6.0 |
innerHTML | Chrome Full support 57 | Edge Full support 79 | Firefox
Full support
63
| IE No support No | Opera Full support 40 | Safari Full support 10.1 | WebView Android Full support 57 | Chrome Android Full support 57 | Firefox Android
Full support
63
| Opera Android Full support 41 | Safari iOS Full support 10.3 | Samsung Internet Android Full support 6.0 |
mode | Chrome Full support 57 | Edge Full support 79 | Firefox
Full support
63
| IE No support No | Opera Full support 40 | Safari Full support 10.1 | WebView Android Full support 57 | Chrome Android Full support 57 | Firefox Android
Full support
63
| Opera Android Full support 41 | Safari iOS Full support 10.3 | Samsung Internet Android Full support 6.0 |
Legend
- Full support
- Full support
- No support
- No support
- Compatibility unknown
- Compatibility unknown
- Experimental. Expect behavior to change in the future.
- Experimental. Expect behavior to change in the future.
- Non-standard. Expect poor cross-browser support.
- Non-standard. Expect poor cross-browser support.
- See implementation notes.
- See implementation notes.
- User must explicitly enable this feature.
- User must explicitly enable this feature.