HTMLElement: toggle event

The toggle event of the HTMLElement interface fires on a popover element, <dialog> element, or <details> element just after it is shown or hidden.

If the element is transitioning from hidden to showing, the event.oldState property will be set to closed and the event.newState property will be set to open.
If the element is transitioning from showing to hidden, then event.oldState will be open and event.newState will be closed.

This event is not cancelable.

Syntax

Use the event name in methods like addEventListener(), or set an event handler property.

addEventListener("toggle", (event) => {});

ontoggle = (event) => {};

Event type

A ToggleEvent. Inherits from Event.

Examples

The example code below demonstrates how the toggle event might be used for popover. The same code is might be used for a <dialog> or <details> elements in the same way.

Basic example

This example shows how to listen for the toggle event and log the result.

HTML

The HTML consists of a popover and a button for toggling it open and closed.

html

<button popovertarget="mypopover">Toggle the popover</button>
<div id="mypopover" popover>Popover content</div>

<pre id="log"></pre>

#log {
  height: 150px;
  overflow: scroll;
  padding: 0.5rem;
  border: 1px solid black;
}

const logElement = document.querySelector("#log");
function log(text) {
  logElement.innerText = `${logElement.innerText}${text}\n`;
  logElement.scrollTop = logElement.scrollHeight;
}

JavaScript

The code adds an event listener for the toggle event and logs the state.

const popover = document.getElementById("mypopover");

popover.addEventListener("toggle", (event) => {
  if (event.newState === "open") {
    console.log("Popover has been shown");
  } else {
    console.log("Popover has been hidden");
  }
});

Result

A note on toggle event coalescing

If multiple toggle events are fired before the event loop has a chance to cycle, only a single event will be fired. This is referred to as "event coalescing".

For example:

popover.addEventListener("toggle", () => {
  //...
});

popover.showPopover();
popover.hidePopover();
// `toggle` only fires once

Other examples

Opening a modal dialog example in HTMLDialogElement

Specifications

Specification
HTML Standard # event-toggle

Browser compatibility

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