onunload HTML Attribute

The "onunload" attribute in HTML is an event attribute that can be added to an element, typically the element, that when triggered, runs a script when the user leaves the page. The attribute value is a string containing the JavaScript code that should be executed when the event is fired.

For example, in the following code snippet, the onunload attribute is used to save user data to a server before the user leaves the page:


<body onunload="saveData()">

The onunload attribute is typically used to perform cleanup or to save data before the user leaves the page, such as saving the user's state, or stopping background tasks. It is also useful for logging user interactions, sending data to server analytics and other similar use cases.

It's worth noting that the onunload attribute is supported by most modern browsers, but not all, so it's important to check the browser compatibility before using it in your website. Also, it's worth noting that some browser will not fire the onunload event if the user navigates to another page by clicking a link or typing a new URL, but only when the user closes the tab, browser or navigate to another page using the browser's back and forward buttons.

In summary, the "onunload" attribute in HTML is an event attribute that can be added to an element, typically the element, that when triggered, runs a script when the user leaves the page. It's typically used to perform cleanup or to save data before the user leaves the page, such as saving the user's state, or stopping background tasks. It is also useful for logging user interactions, sending data to server analytics and other similar use cases. It is supported by most modern browsers, but not all, so it's important to check the browser compatibility before using it in your website. Also, it's worth noting that some browser will not fire the onunload event if the user navigates to another page by clicking a link or typing a new URL, but only when the user closes the tab, browser or navigate to another page using the browser's back and forward buttons.