ToggleEvent: oldState property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since November 2023.

The oldState read-only property of the ToggleEvent interface is a string representing the state the element is transitioning from.

Value

A string. Possible values are "open" (the popover is going from showing to hidden) or "closed" (the popover going from hidden to shown).

Examples

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

// …

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