Web/API/HTMLSlotElement/slotchange event

The slotchange event is fired on an HTMLSlotElement instance (<slot> element) when the node(s) contained in that slot change.

Note: the slotchange event doesn't fire if the children of a slotted node change — only if you change (e.g. add or delete) the actual nodes themselves.

Bubbles	Yes
Cancelable	No
Interface	Event
Event handler property	None

In order to trigger a slotchange event, one has to set or remove the slot attribute.

Examples

element.setAttribute('slot', slotName);
// element.assignedSlot = $slot
element.removeAttribute('slot');
// element.assignedSlot = null

The following snippet is taken from our slotchange example ([[../../../../../../../mdn.github.io/web-components-examples/slotchange/index|see it live also]]).

let slots = this.shadowRoot.querySelectorAll('slot');
slots[1].addEventListener('slotchange', function(e) {
  let nodes = slots[1].assignedNodes();
  console.log('Element in Slot "' + slots[1].name + '" changed to "' + nodes[0].outerHTML + '".');
});

Here we grab references to all the <slot>s, then add a slotchange event listener to the template's second slot — which is the one which has its contents changed in the example.

Every time the element inserted in the slot changes, we log a report to the console saying which slot has changed, and what the new node inside the slot is.

Specifications

Specification	Status	Comment
DOMThe definition of '"Mutation observers" and slotchange event' in that specification.	Living Standard	Initial definition

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
slotchange event Experimental'	Chrome Full support 53	Edge Full support 79	Firefox Full support 63 Full support 63 No support 59 — 63 Disabled' Disabled' From version 59 until version 63 (exclusive): this feature is behind the dom.webcomponents.shadowdom.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config. No support ? — 59 Disabled' Disabled' Until version 59 (exclusive): this feature is behind the dom.webcomponents.enabled preference (needs to be set to true) and the dom.webcomponents.shadowdom.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.	IE No support No	Opera Full support 40	Safari Full support 10.1	WebView Android Full support 53	Chrome Android Full support 53	Firefox Android Full support 63 Full support 63 No support 59 — 63 Disabled' Disabled' From version 59 until version 63 (exclusive): this feature is behind the dom.webcomponents.shadowdom.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config. No support ? — 59 Disabled' Disabled' Until version 59 (exclusive): this feature is behind the dom.webcomponents.enabled preference (needs to be set to true) and the dom.webcomponents.shadowdom.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.	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

Experimental. Expect behavior to change in the future.'

Experimental. Expect behavior to change in the future.

User must explicitly enable this feature.'

User must explicitly enable this feature.

See also

HTMLSlotElement

HTMLSlotElement: slotchange event by Mozilla Contributors is licensed under CC-BY-SA 2.5.