The ToggleEvent() constructor creates a new ToggleEvent object.

type

A string representing the type of event. In the case of ToggleEvent this is always toggleevent.

init

An object containing the following properties:

newState

A string representing the state the element is transitioning to. Possible values are "open" and "closed".

oldState

A string representing the state the element is transitioning from. Possible values are "open" and "closed".

A developer would not use this constructor manually. A new ToggleEvent object is constructed when a handler is invoked as a result of a relevant event firing.

For example:

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

// ...

popover.addEventListener("beforetoggle", (event) => {
  if (event.newState === "open") {
    console.log("Popover is being shown");
  } else {
    console.log("Popover is being hidden");
  }
});

• Popover API