The HTML onpagehide event
The HTML onpagehide attribute runs JavaScript when a page is hidden, e.g. navigating away or entering the back/forward cache. It is an inline handler for the pagehide event; in modern code prefer addEventListener('pagehide', …).
Overview
The onpagehide event attribute runs JavaScript when the page is hidden. In JavaScript the event itself is named pagehide. Drop the on prefix when you call addEventListener.
It is a window-level event rather than one tied to a particular element, so it is handled on window. These events cover the page lifecycle, navigation, network status, messaging and similar global concerns.
You can wire this up with the inline onpagehide HTML attribute, but the modern, recommended approach is window.addEventListener('pagehide', handler) in JavaScript. That keeps behavior out of your markup, lets you attach several handlers to the same event, and makes them easy to remove. The inline attribute is fine for quick demos.
Syntax
<body onpagehide="handler()">…</body>
window.addEventListener('pagehide', handler);
Best practices
- Prefer
window.addEventListener('pagehide', handler)over the inlineonpagehideattribute; it separates behavior from markup and allows multiple handlers. - Attach these on
windowwithaddEventListenerrather than as <body> attributes. - Keep these handlers fast; they run at moments that affect the whole page.
- Remove listeners you no longer need to avoid leaks in long-lived pages.
Frequently asked questions
What is the onpagehide event?
pagehide.Where do I attach this event?
window: these are global events, not tied to a single element.Can I use it as a body attribute?
onpagehide attribute on <body> is forwarded to the Window object, so the handler is registered on window rather than on the body element itself.Should I use the onpagehide attribute or addEventListener?
window.addEventListener('pagehide', …) in JavaScript. The inline onpagehide attribute works but mixes behavior into the markup and allows only one handler per element.