What are the JS events that don't bubble up?

What are the JS events that will not bubble up?

JavaScript is a powerful scripting language that adds interactivity and dynamics to web pages. In JavaScript, event-driven programming is a very important part. Events refer to various operations performed by users on web pages, such as button clicks, mouse movements, keyboard input, etc. JavaScript responds to these events through event handling functions and performs corresponding operations.

In the event processing process, event bubbling is a common mechanism. Event bubbling means that when an element triggers an event, the event will propagate to upper elements layer by layer until it reaches the top-most element. During the event bubbling process, events can be handled in two ways: capturing and bubbling.

However, in JavaScript, not all events have bubbling characteristics. Some events do not bubble up, that is, they can only be processed on the element that triggered the event. Next, we'll cover some common JavaScript events that don't bubble up.

1. focus event: Fired when an element gains focus. For example, when the input box is focused, the focus event will be triggered. This event does not bubble up and can only be handled on the triggering element.
2. blur event: triggered when an element loses focus. Similar to the focus event, the blur event does not bubble up and can only be processed on the triggering element.
3. submit event: Triggered when the user submits the form. This event can only be handled on the form element and will not bubble up to the parent element.
4. Input event: Triggered when the user enters content. This event is usually used to monitor the content changes of the input box in real time. Input events do not bubble up and can only be handled on the triggering element.
5. change event: triggered when the value of a form element changes. This event can be used to listen for changes in the selection of optional items. The change event can only be processed on the triggering element and will not bubble up to the parent element.

In addition to the above events, there are many other events that will not bubble up, such as load event (triggered when the page is loaded), unload event (triggered when the page is unloaded), reset Events (triggered when the form is reset) and so on.

For events that do not bubble up, we need to pay attention in the event handling function to only handle the triggering element and not bubble up to the parent element. Otherwise, unexpected results may occur.

To sum up, there are many types of JavaScript events that do not bubble up, and each event has different application scenarios. For developers, understanding these different event characteristics can better apply event processing mechanisms and improve the interactivity and user experience of web pages.

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